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65wildcatconvt

safe redline for 401 nailhead with 115k miles

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hello all- -30 below up in northwest wisconsin this morning so dreaming of summer. anyway, an old high school buddy of mine challenged me to a 1/4 mile race this coming summer on a deserted county road.

my car is a 65 wildcat convt with a 401 nailhead engine and the th400 tranny. the running gear has not been rebuilt or touched as far as i can tell. the car has 115k miles on it i think ha ha.

so i dont generally beat the car and i maintain it well, just curious what you guys would spin these motors up to with minimal chance of explosion? i love the nailhead engine but dont know much about it as we usually souped up chevelles and novas in high school 33 years ago.

i am thinking 4000 rpm max... and would you guys leave the colunm shifter in drive or shift manually?

car i am racing is a 69 buick lesabre 4 door i think with a 350 2 bbl carb so if i lose i will hang my head in shame.

i read an article on the net a while back saying the nailhead engines have a steel crank and rods if i remember correctly heard they are a tough motor, was at a car show once and a couple guys said they tried to kill a beater wildcat they had back in the 70s and they said the running gear would not die.

Edited by 65wildcatconvt
correct spelling (see edit history)

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Here's my story.....

I've had my 65 Electra with a 401 since 1973 and I'm on the third engine. The saga......

Bought it in 73 when a junior in HS. The engine blew on Rt 80 (1978) heading west through the Pa. mountains. Had about 135K on it at the time. The number 7 rod broke or came loose and took out a section of the cam. Lots of scrap metal in the oil pan when I took it apart.

Bought a 79 Buick Skyhawk till I could find another engine.

Found a replacement engine in 1980.

Had the car at a bodyshop in 1981 and the guy said it would not start when he tried to move it. I went over to get it started and noticed that it was backed into one of the stalls. So I was suspicious. I think they were out hot rodding it and guess what.....It had a broken #7 rod too and it took out a section of the cam. That engine had less than 100K on it. I was not a happy camper.

My old Buick sat in my garage till about 2002 when I acquired a 'new' 401 that had never been installed in a production car (that's another story). I started the long process of fixing and restoring my old car in 2003 or so and it is mostly done. I've got less than 2000 miles on her now.

If I really liked the car, I'd pay him $20, tell him he won, and live to drive the old nailhead another day.

Bill

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Just curious wmsue, did your new engine come from an aircraft starter?

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great story bill, ya i am 51 years old and i feel like throwing a rod every now and then esp when i am at work... believe me i love this old car and am not in a position to spend a lot of money on it right now, just very grateful i even have it.

i remember reading something about nailhead engines being used to start sr71 spy plane engines in the 60s i think

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SR-71 start carts used two "Buick Wildcats" connected to a common transfer case to start the jet turbines. Not so much the rpm's but the torque to hold the turbines at speed until they would ignite. Buick offered tachs in the mid 60's and if I'm correct, they redline out at 5,000. That's still a bunch of rpms for this engine. Nailheads ARE NOT Chevies, they don't rev up. You get your power from the low end torqe. Don't try to build them like a Chevy.

Ed

Edited by RivNut (see edit history)

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I don't presently own either car, but I essentially have driven both back in the day. I owned a '65 Electra 225 with the 401 and my parents bought a new '69 LeSabre 4 door with a 350 back in 1969. The Electra would smoke the tires, but the LeSabre would just go.

I remember racing my then wife at a stoplight while I was driving my '63 Impala SS with a 327. She was in the deuce and a quarter and when the light turned green she floored it. The big beast roared, but just spun the tires while the little 327 Chevy just went. I think the comparison might go something like that. Not quite as dramatic as the weight difference between the Wildcat and LeSabre is not as great, but still the same outcome I think.

SO, I suppose it boils down to driving skills. If you can keep your foot out of it until you get going a bit, you stand a much better chance of winning that race. JMHO, but it was fun to remember...

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When I had my 66 Gran Sport ( w/ 4 speed) I kept going through water pumps. Finally one pump came with a warning tag not to run the engine over 35 MPH in first gear. I don't remember the RPM of 35 MPH in first, with the 3:42 rear. Maybe someone can help with that?

Also when I was driving Dads 65 Electra in my early years, I went through 3 sets of motor mounts. That engine however did round the clock twice without a rebuild or even a valve job.

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EACH GM engine brand had their own particular torque characteristics and endearing qualities. In the case of the larger Buick V-8s, it was "torque". Using torque correctly can trump "high rpm horsepower" as it gets you there before the other guy's horsepower at higher rpm can start to happen (with gearing being similar).

Each engine also has their own "critical rpm" regarding things coming apart, by design. I found a formula for that years ago, but don't remember plugging the Nailhead specs into it.

For a basically stock motor, I'd say 5K rpm would be a good place to limit things. Also remember that with a manual trans, or an automatic to a lesser extent, although the tach might indicate "5000", by the time the shift completes the rpm can be a bit higher.

Also, as the Chevy 327 story indicates, tire smoke might look and sound neat and powerful, but some Chrysler drag racing research (in the later '60s) indicated that the optimum tire slip under acceleration was 10%. Make a respectable noise, but also go forward, quickly. With torque motors, as Buick nailheads tended to be, have to have a little discretion off the line to optimize forward motion.

One thing I'd be concerned about is the timing chain and if it's been replaced. Plus that the engine had a fresh oil change and reasonably-fresh spark plugs and really good plug wires. These things would make it more fun and efficient to drive normally, too.

If the 350 is a 2bbl, it could well be the "small" 2bbl Rochester carb with the 1.44" throttle bores. They run well, too, but really need the additional air flow of a 4bbls' secondaries to have better power above about 3000rpm.

Might be best if y'all remain friends. If somebody needs a barn pulled down, then you'd get the call. If somebody needs more economical transportation, the LeSabre gets the call. I.E., no race.

NTX5467

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Well, I think your car should have the variable pitch converter. Assuming it does and its working properly, that's going to weigh in nicely in your favor. For extra insurance, an inexpensive and big-bang-for-buck addition is to have your distributor modified so you can run more initial advance. Tom Telesco (board name Telriv) can help you with that. Make sure your carburetor is well tuned as well as engine in general. Be sure to remove any unnecessary weight from the car before the race. Shift manually. You shouldn't need to go more than 4000 rpm to win. The low end torque of the nailhead and switch pitch will win the race assuming friend has a stock 350.

Often, driving skill is critical in these types of races. Do some solo test runs ahead of time to get a feel for how the car responds and hone your techniques.

Wouldn't hurt to do a compression test on your engine just to see what kind of shape the internals are in.

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thanks for replies everyone..

alright, when i purchased this car in 2012 it would barely pull itself up onto my trailer, but did not smoke or knock so i took a gamble. under the hood basically looked like it was 100% original as in everything neglected and not ran very often. i got it home, repaired some leaks, found 3 spark plugs finger tight, looked like original plug wires etc. anyway i got lucky and it runs strong and smooth with just basically a tune up. never got around to a compression check yet just because it runs so nice but its on the list.

i did some metal repair and now am prepping to paint the last 1/4 of the underneath of the car with rust bullet, as i did most of the undercarriage last winter. then changing the tranny fluid and filter as long as she is up on blocks. the tranny shifts decent and smooth, i have always been a big fan of th th400 as i had a big block 71 nova with th400 (homeade, car was originally a 6 banger with a powerglide) and a 69 chevelle with 396 chevy motor and th400 ( also homeade car originally 307 with powerglide or th350 cant remember) back in high school. i think there are 2 wires coming off the trans so may be switch pitch, it has some funky downshifting apparatus up on the carb that is not hooked up...

one of the reasons i was really attracted to this wildcat was: 401 big block from factory- somewhat high compression motor 10:1 or so i think, from the factory-cool- 4 bbl carb- factory th400- kind of a slight lumpy cam from factory- that is cool as heck ha ha. and burns rubber just halfway stabbing the throttle- cool!

so one of the first things i did- dual exhaust of course!

my goal is to keep working on the car in the winter, and always keep it drivable in the summer if possible

so i will race, just cause these are my old best friend hot rodding buddies, but will go half throttle starts and then somewhat hammer it down if i need to and im not going over 4 grand rpm even if i lose, i just love the sound of this motor!

was going to hold off on timing chain one more year but maybe if time permits should do it... what do you guys buy for timing chain sets??? steel gears? napa parts?

there are not a lot of motorheads around anymore so thanks for listening

Edited by 65wildcatconvt (see edit history)

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The pan bolts above the crossmember are the hardest part of getting this stuff out of the pan:

002001.jpg

Bernie

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60flattop- you got me there!:D alright now only going 3750 rpm ha ha. believe me this is all in good fun with my excellent friends and if no race happens they are cool with that. truth is i love to hear the pipes on the car so i rev her out a little once in a while...just cant help it

johnd1956- or anyone,, my car has a approx 10" long thick steel bar bolted to the block lower driver side front and looks like it is supposed to bolt to the frame??? it looks original and factory made but is hanging there, is this some kind of torque bar or something? did gm ever do anything like that?

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The local Buick Performance Group used to rent out Texas Motor Speedway once a year for their annual Buick Race Day. It was bracket racing so it didn't really matter how fast you were as long as you were consistent. I raced my 1966 Wildcat a few years. It was completely stock, including bias ply tires. I would drive around the water used to wet the tires for initial burnouts so that I wouldn't spin the tires. I left it in Drive the entire time and would floor it when the light turned green, as quickly as I could without spinning he tires. Once I got passed the point of spinning the tires, I held it down to the floor the entire time and let the TH400 transmission shift by itself. I ran 16.50 in the 1/4. It was very consistent running it that way, and I won 1st in my bracket the first year and second in my bracket the second year (I ran a bit faster than 16.50 and broke out on the final race). Anyway, don't be afraid to just leave it in Drive and floor it. It can handle it.

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txbuicks-my same friends and i moved to texas in 1983 as there was no work in nw wisconsin, we drove down a 72 chevelle i had, we finished putting the motor in it the night before we left. 1500 mile trip, no shift linkage, had to leave it in drive all the time ha ha shifted it under the car right on the tranny if you needed to. im still working for the same company i found a job with down there 33 years ago up north in my home state... great memories of texas, what a great state.

have a good weekend everyone

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As for timing chain sets, the "classic" deal is just the normal auto supply full-metal gearset, using the chain and the cam sprocket only. When I put a timing chain in my '77 Camaro at 92K, the factory chain was still pretty decent, but some Buicks (I've known about, even back then) usually needing something by 80K. That's about when most of the factory sprockets would lose some of their plastic/nylon teeth. I put a Cloyes Plus Timing Set in the Camaro. Something of a hybrid between a "true roller" timing chain and a normal chain. I put it in at 92K (along with a cam upgrade) and it was still in the motor when I swapped a 355 in its place, about 625K miles later. The 355 has one in it, too. Has a little "bicycle chain noise" at idle, but I know that sound and that's fine . . . just as some like the sound of solid lifters at idle.

KEY thing would be to get at least OEM quality parts. Considering what can happen when a chain/cam sprocket can fail, it's cheap insurance. I don't know that you need to get one of the timing sets where you can install it slightly retarded or advanced, just put it in "straight up" normal. I also made sure to pour some motor oil over the new chain when I put it in, plus some cam assembly lube on the teeth and on the backside of the cam sprocket. If you get one of the roller chain style sets, you'll need to change BOTH the cam sprocket and the crankshaft sprocket. If you do a normal-style chain, you can do what I mentioned above, just change the cam sprocket and the chain.

The THM400 is a really good automatic transmission. They have an electric-triggered WOT downshift switch, either on the carb or under the instrument panel (above the accel pedal). Two wires would be the kickdown and the switch pitch controls, I suspect. Back then, I believe that most of the THM400s would shift in the 4400-4600rpm range at WOT, in Drive. Maybe 4800-5000rpm in some "performance" applications?

Keep us posted on your progress.

Enjoy!

NTX5467

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Around 1971 or '72 my sisters Chevy Caprice was recalled for bad motor mounts. The fix was a steel cable attached to the motor mount and wrapped around the bracket for the A frame. The 65 Electra we had was not recalled before my father sold it, but I have seen that "fix" in at least one other 65 Electra.

I doubt that steel bar you mention was attached directly to the frame or there would be a lot of engine vibration transferred through the vehicle. But that does not mean it could not be attached to the frame by a cable or a piece of chain. In the case of the Electra, the first time the mounts broke we kept hearing a loud scraping sound when accelerating aggressively. We found out the hard way that that noise was the fan hitting the fan shroud while the engine flipped on its right side in it's cradle. The other two times as soon as we heard that noise we knew what was up and backed off the gas. My brother was actually driving when the first set broke. As I recall, he was driving dad home from work and he said listen to this. The light turned green, he stabbed the gas, the engine flipped dragging the accelerator to WOT, and all my brother could think of was two feet on the brake pedal while it was still burning rubber and pushing forward with locked front tires. Dad was flipping out but managed to reach over and turn off the ignition before anyone got hurt. Glad I missed that ride.

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thanks everyone for the great info

johnd- i have been wondering what that steel bar was for, for 3 years, i always just left it there in case i ever ran into someone that knew what it was for. no matter what way you moved it, it would not line up to bolt to anythlng,but makes perfect sense if there was a cable or short piece of chain on the end of it...

sure is strange where a thread can take you .

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Very good to do that timing set and the old 'soup can' pistons of the day can often break skirts after all the years and miles-so keep the revs reasonable and your ears open-good luck

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Back in the mid 1990's I was painting the rearend housing for my Riviera on a Saturday night and listening to a '50's Rock radio station. I couple of guys from a town north of me called in a request. The DJ asked a few questions and it turned out they were in the garage working on a 1966 Chevelle.

I called in a request a little later and he asked what I was up to. I told him "Painting the rearend of my '64 Riviera." The DJ said "Wow! That's detail. are you going to a show?"

I said "Nah, I just wanted it to look nice 'cause its all the Chevelle guys will see."

Bernie

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alright, high of 2 below today but I got a chance to look at that metal bracket after sawing some firewood.

turns out it goes from the front of the motor mount driver side to the bottom of the power steering pump.

in my defense before you guys laugh, it must be noted the bracket was bolted on backwards to the motor mount and facing down to the ground by someone in the distant past and also I have not seen a car like this in person since 1979.

first time I remember seeing a wildcat I had just started a full time job pumping gas at a full service station. I was 15 and in high school, did not know squat about cars. this guy pulls up in this car and says "fill it up" so I say yes sir and proceed to look for the gas door or cap. checked both sides of car... pulled on license plate thinking "its gotta be back here" I think I kinda bent the poor guys license plate... looked on the sides of the car again and scratched my head. finally looked under the car and saw where the filler pipe went up to... pulled on the buick emblem, thought hey this is kinda cool ha ha so ya I can be kinda thick skulled.

so I took the bracket off the motor mount today and tried flipping it around and put it more towards the top of the motor and then saw that it goes from motor mount to power steering pump, at least I hope that's right

this car has been kind of weird and I think it has some stories to tell as the grill was in upside down,( it took me a while to figure that out), half the exhaust manifold bolts were loose, it has a different front clip,(at least a clean straight and rust free one) there was a note in the glovebox stating the trans is original but not saying anything about the motor, from a guy in Colorado in 2005... there are some oil change stickers on the door from Chicago in the 60's, had a Colorado plate, title, and air sticker from the 90's and I got It from a guy in iowa 3 years ago that said he just let it sit for years.

60flatop you made me laugh again, I remember thinking chevies are the best when in high school, now any old car is cool as heck.

and you just don't see any of these old buicks up in my neck of the woods, have never seen a wildcat under the hood before this one. the ones up here rotted away long ago. I always liked the body style and the way these cars look tho. and i really like the running gear in them now that I know a little more more about them.

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A power steering pump rear bracket/brace can be possible (although I don't know specifically what's on the particular model of Buick you have). Might have been a particular thing they were trying to minimize or keep from happening?

When that car was designed, the "center, rear" gas tank filler access was quite common, including behind the rear license plate. Just be glad it wasn't a mid-50s Cadillac or Chevrolet!

NTX5467

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Fifty year old car with 115k miles---pretty good chance your hydraulic lifters and old valve springs will decide your redline right quick.

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The bracket makes sense, as long as it's being attached to the engine side of the motor mount. Can't quite recall my dad's 65 Electras bracket. But any Electra would provide a clue as to the routing of the same.

The 65 Wildcat is a super car. In my opinion, you are a lucky guy to have one. How about some pictures to sooth the souls here?

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thanks all- i am borrowing a camera from my girlfriend this weekend and my #1 goal is to get some pics and get them posted next week if possible so you guys will see the car is for real.

found a sun tach in a box from 1982 so going to discreetly mount it in the car somewhere and set the redline needle on 4 grand.

thought i heard somewhere the th400 modulater is adjusable with a screwdriver... as in possible to firm up the shifts a little, has anyone ever heard of that? its a tad mushy for me, i put a shift kit in a th400 back in 82 not sure if i want to go that route...

my car is basically a "20 footer" or like number 3 condition but i am super blessed to have it and really enjoy trying to preserve it and prolong its lifespan, but it will never be a show type car so i think a few small performance mods would not detract from it. goal is to always have it driveable in the summer months so i still have 3 months to get her ready ha ha.

Edited by 65wildcatconvt
spelling (see edit history)

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