want to Upgrade a 455 1972 Stage 1 Stock - What is best route?

[Takis]

I am thinking about adding more horsepower to the 455 by upgrading Cam and heads.  Then will alter carb to a more robust cfm to 820 with ne intake manifold...  also add converter for gas to get quicker to the rpm where hp RPM range is at...

 

i realize this is a very large upgrade, but any facts to do it or not too.. or what heads and carb should be used since I do not want to alter the hood... btw, this is going into a 68 GS, not a 72 with the hood scoop already there.

 

Thanks much.

 

Taki

[NTX5467]

Rather than all of the "g750cood to talk about at the cruise" stuff, why not go more toward efficiency?  Which should also unlock some better driveability at the same time?

 

You can brag about how much carb, how much cam, what it dyno'd at, etc.  BUT if it doesn't scatter stuff until it get to a higher rpm, what real good is it on the street in normal driving?  The driving range you're normally in, rather than at the top of the rpm band!  Less total power, but more useable in daily driving rpm levels (i.e., TORQUE) is what burns the tires off-idle, NOT 6000rpm horsepower!

 

As these were emissions engines, an optimized centrifugal advance curve in the distributor, one which BUICKS like (not the generic Chevy motor!!!), plus a good vacuum advance curve, plus a more-optimized fuel curve in the QJet or 750cfm street carb helps in the efficient power orientation, too.

 

I'm NOT mentioning self-learning fuel injection for a few reasons.  One of which is that I've PM'd with some people who have them and never could get the fuel mixture just right for their engines.  One was from a forum user who had one put on his Buick 430 Electra, which did high-teens economy on the highway, but now doesn't get past 8mpg.  Not sure what went wrong, but something did.  So, with all of the newer carbs, as the Street Demon, I tend to lean toward bolt-on carbs, then finessing them for the application.  PLUS, the cost of these EFI kits is still not a cost-effective (from fuel savings) compared to a $500.00 (or less) new carb.  Be that as it may.

 

Upping the compression can help, probably, but I'm not sure how that could be done on that motor.  With just heads or with pistons, or combinations thereof.  MUCH has been learned in combustion chamber dynamics since that engine was designed, by observations.

 

Exhaust system?  Probably should be 2.50" pipe as a good size for that size motor, with some quieter low-restriction mufflers.  A "torque" motor that "rpms" can be a good thing, but it shouldn't need to go to 6000rpm to get results.  Aim more for 5000rpm as the top rpm.

 

Get the car so it has super-sharp off-idle throttle response and similar when cruising at 1500rpm levels.  You'll have more fun and spend less money getting there.

 

Just some thoughts,

NTX5467

[carbking]

How and what one does often is a function of one's budget, AND the guy at the local speed shop that wants to help one with one's budget

 

Street engines, and engines for trailered race-cars are two different items. The rest of this post is directed toward a street engine.

 

Three external (read less expensive than internal) options are: (A) carburetion (maybe), (B) distributor, and (C) exhaust.

 

Covering the distributor first - most of the US V-8's by 1972 had very little initial advance, and a distributor that cranked in the rest. Not a distributor guy, so will leave specs to those that are; but more initial advance (up to a point) is generally a good thing.

 

Willis (NTX5467) covered the exhaust.

 

As far as the carburetor/intake manifold: Lots of early 1970's Buick carbs were 800 CFM, and the Pontiac and Chevy dudes have been migrating them to Pontiacs and Chevvies for years. The fact that the WOT is 800 is nowhere near as important as the fact that the primary side is 200 versus 150 for the 750 CFM carbs. When Carter brought out the TQ in 1969 (race-only), and folks used them on performance street-cars, it was found that the transition from primary to secondary was MUCH smoother using the slightly larger primary. Buick figured that out in 1970, and Pontiac performance engines used larger primary carbs beginning in 1971. By 1976, virtually all of the Q-Jets were 800 (200/600).

 

For street use in street RPM ranges, the aftermarket intakes will gain style points, AND LOSE LOW-END TORQUE! Your choice, style or torque.

 

So, suggestions:

 

(A) carburetor - determine if yours is a 750 or 800. If 750, acquire an 800 (Q-Jet or the Carter GM TQ). If you go with the Q-Jet, buy Cliff Ruggles book on the Q-Jet. (OPINION) NOTHING new will outperform either of these two on the street, and probably won't come close unless set up by a professional.

(A-sub-a) manifold - stock Buick

(B) distributor - talk to a distributor dude, nothing wrong with a modified (curve) GM original.

(C) exhaust - 2 1/2 inch pipes, and good mufflers. Personally, I DETEST tube-headers on the street (really like to be able to listen to music).

 

The above should be good for a healthy performance increase, and won't bust the budget.

 

Have fun.

 

Jon.

 

[Takis]

Thanks for the great info NTX and carbking.... 

 

Actually, I gave the go ahead over the weekend to the custom garage that will be doing the upgrade...

 

One determination was the carb - currently, the stock (I believe) rochester carb is on it.. do not know cfm...  but I will be getting an 820 cfm pro series... the mechanic/engineer has used these in the past and feels comfortable - I know they are expensive...  $650-800 

 

I am getting a new alum manifold to better match the larger carb.

 

Getting all new electrical.... MSD Distributer/Coil/Ignition Firecore Spark Plug wiring

 

With that, with the point that was made with RPM, placing a converter in to get the engine to better rev to where the HP and torque is at quicker and smoother... hopefully, there will not be any hesitation in the gas flow how I have now.. meaning, when I floor the gas, there is that initial 1/2 second stall hesitation and then things kick in

 

Finally, since I was getting so much into the upgrade - I decided to go ahead and change the larger alum heads and cam for the 455...  do not know that ,info yet. but I know I will be pushing the compression to 10:1 or so...

 

btw, I think I have 2.5" exhaust already.  I need to double check...  because the headers where not in the price of the upgrade.

 

So, that is the new upgrades... My existing 455 was upgraded about 7K ago too with mainly stock stuff - still runs great, just got used to the zoom.. and want more of a zoom...

 

Likewise, all this started because I was leaking a little oil from my manifold that I needed to fix...

 

Again, any thoughts are welcome...  

 

I will keep everyone posted...  Likewise, I will place before and after pics along with during the build pics...

 

Takis

 

 

Edited May 20, 2019 by Takis (see edit history)

[carbking]

2 hours ago, Takis said:

 

 

If the car is still together, run three 0-60 times and get an average.

 

Once the modifications are done, do the same thing, and compare the results.

 

You may be surprised.

 

Jon.

[Takis]

Hello Everyone..

 

After a couple of months, I am at the point where I have broken in the 500 mile milestone, changed oil to normal oil, and now surpassing the 3000RPM point of the engine by taking the car on the freeway.  Before the 500 mile, I was babying and not taking it past 3000RPM.  

 

As I was driving the car over the weekend, where I got it back from the engine re-builder on Friday, when I go to ~3200RPM, I hear a squealing...  Now, to me it sounds like the water pump...  I am taking it in tomorrow in the morning to the shop, because I am on vacation this week and want to get it fixed as soon as I can to enjoy it...  Now, I did check power steering fluid.. it was a little low, but tapped it off.  I do not believe it is it, but you never know.  It could be one of the pulleys too..  I do not know...

 

I realize this is a little late to ask for advice before I take it in tomorrow morning... but there may be a consensus among you folks.. I know, because this forum has allot of good and smart people on it.

 

oh, another thing...  when I rev it up to 3200 and then push more to 4000, the squeak still stays there... as for getting louder, I do not know, because the rev of the engine kind of overtakes the squeaky sound...  I did try to push it 8-10 times over the weekend, just in case it was a anomaly because the pulleys were sitting for a few weeks...  This did not happen to my previous engine when I would go past 3000 or 4000RPM.. so this is something new...

 

 

Likewise, I do not know who to blame.. just the parts are old, or the engine re-builder did not check these things before putting the engine together...

 

Also, I did check belts and them seem tight

 

 - only the power steering seems a little loose... but I am not the expert.. also, I do buy that belt spray and placed it on 5-6 times already... that did not work.

 

OK.. I think I have given you guys the whole story.. any suggestions are appreciated, and of course, after tomorrow, I will know better after I take it in... but, it would be nice to know what you folks may think.

 

Hopefully, everyone is having a nice summer.

Takis

 

 

 

[EmTee]

A worn belt can still slip/squeal even if it is tight...

[Takis]

Thanks.. but I do know that they place two new belts (not using air conditioner)...  but this brings a point, that I may need that second belt for more sturdiness around the water pump - but I did not have it before the build, but maybe because of the more power, the additional belt is needed.  I guess, I will find out tomorrow.. Once fixed, I will let post the resolution.

Thanks

[Frank DuVal]

Run with the belts off and see if the squeal is still there.

 

If a pulley has two grooves, then there should be two belts in there!

[Takis]

Well, Frank was correct...  I worked on this with a friend... the auto garage was closed yesterday.

 

As I mentioned, I am running the engine without the air conditioner in it..  thus, I was not using the second set of belts.  So, after I added the second belt, no more squeaking.  I guess the upgraded engine made a difference, where again before, I was running the previous non-rebuilt engine with just one belt.

 

But, there is a caveat.   there is not air conditioner , where there would of been a different sized belt - a few inches lager than the inside belt...  this time, the outside belt needs to be ~ 1/8" smaller than the inside belt, even though logically, they should be the same size.  I guess something with the pulleys and maybe the depth of the pulley's notch.  what I am explaining is this.. then inside belt length is 51" while the outside belt length needed to be 50-7/8"...  then both belts when tightened via the alternator slider are bought taught. 

 

Thanks for everyone's advice.. I am happy that this was a simple fix...  I am happy, that the auto garage guys did not disappoint me and put in a bad water pump too...

 

Now, I can start pushing the engine a little and see if all this extra money and time in upgrading the engine really does make a difference in power and speed..

 

The current observation  is that the engine does sound really good and mush louder than before.. but I do not how much more sound the 3" mufflers are adding when compared to my 2-1/2" pipes from before....  there is a difference in the larger cam that I added too, definitely - again from a sound perspective.  Now, it really sounds like a muscle car, or more of a race car.

 

Also, I did put in switch to more expensive mufflers to subdue the overall sound on each side - no H pipe - but pipes go all the way to the back.. because I was afraid of the cops pulling me over due to the load grumble especially when going past 2000 RPM - with these new mufflers, the bark went to a smooth grumble, and was worth the money to limit the volume, especially living in a urban area...

 

No oil leaking (at least yet)... gas mileage almost the same as before - ~8 miles to gallon.  Since the engine got bored out, the compression ratio is around 10:1,  so i used 93 Octane with the accelerator every fill up...

 

Now, it is just time to drive it and enjoy it...   and hopefully, being a rebuild, having no issues the next 1000 miles...

 

I will place some pictrues shortly and keep everyone posted...

 

Takis

[EmTee]

On 8/20/2019 at 9:36 AM, Takis said:

more expensive mufflers to subdue the overall sound on each side - no H pipe - but pipes go all the way to the back..

 

A balance tube connecting the two sides of the exhaust system (aka: "H-pipe") will not only help quiet the exhaust, but also improve flow/scavenging.  I suggest adding one as close to the manifolds outlets as possible.  Typically it would bridge the two pipes somewhere just after the forward driveshaft U-joint. 

[Takis]

Here are some pictures of the rebuild....  Am at ~1100 miles total so far on the engine and everything is fine.  Only thing, no leaking oil, but engine is burning oil (I think) - needed to add a quart of oil at ~500 miles after 500 miles break-in oil change.  I do have smoke come out of the top of my header covers where I placed hoses on the breather to take the pushed up oil to the ground while running the engine.

 

Anyway, here are all the pictures....  

Here are some pictures of the rebuild....  Am at ~1100 miles total so far on the engine and everything is fine.  Only thing, no leaking oil, but engine is burning oil (I think) - needed to add a quart of oil at ~500 miles after 500 miles break-in oil change.  I do have smoke come out of the top of my header covers where I placed hoses on the breather to take the pushed up oil to the ground while running the engine.

 

Anyway, here are all the pictures....  

[Takis]

Now that I have broken in engine..  ~2200  miles into engine...

 

The car is a little quicker from the start...  but where it is much quicker is when I am at ~30mph and I floor it...  (it is a TH400 3 speed, not 4 speed transmission) To be honest, I am still babying the engine, and with the stall converter being around 2800-3000rpm, I really have stepped on it from stop yet.

 

Overall, knowing the engine is baselined and done right and new, I feel happy about.

 

Yes, it cost 3 times more than I was planning on spending initially (was just going to do the intake and carb)...  but now that I have finished driving it for the summer/fall, I feel it is a good investment and overall feel better driving the car...  as for feeling the car to be much faster due to the ~100 additional hp (think I am around 500hp  - just engine), it is a little faster.. but now she sounds like a muscle car due to the larger pipes, larger cam.

 

Maybe next year, I will add some nitro setup to the rebuilt 455 engine. 

 

Now, going to rebuild the numbers matching 400ci engine that came with 68 GS this winter...  That will be my next post. 

 

Have a Merry Christmas and New Year everyone!

 

Takis

[Takis]

I think there is a follow up...  due to some incorrect info I placed...

 

basically what happened is the issue with the belts...  the belts should be the same length... in above post I thought I fixed the problem by using a slightly longer inner belt and shorter outer belt.  Well, that messed with the charging to the alternator and eventually decaying and dying of y larger battery.  The voltage on my meter showed 14-15 volts which I thought was fine, but it should be between 13-14 volts, as it is now, after I fixed the belt situation.

 

As of now, I am still very happy with the overall investment with the engine...  the next upgrade I will be doing to the car is changing the transmission and rear end to capture all of the true power coming from the engine,  The 3 speed and 3:23 rear end is quick, but if I had a 4th speed and a 4:10 rear end, the car would be much quicker...  But, I do not have all the details yet, but this will be next year's investment.

 

Hope all are OK with this Craziness currently going on in our country.  Take Care.  Taki