Nailhead power

[alini]

This weekend I am ripping the engine out of the frame and removing the heads to ensure the engine is in fact useable. My son is currently a student at the School for Automotive Machinists in Houston, Texas. They teach engine rebuilding, with the intent being POWER. Once I ensure I can use this block and heads, its getting crated and sent to him for the rebuild. This tackles a few things for me. 1) My son is part of the project 2) It saves me on the cost of rebuild because there is no labor and the parts will come with a discount (he gets a student discount when ordering parts through the school. 3) I get a blueprinted engine with a dyno tune back, that I just need to drop in and run. I will get a full list of measurements, parts, flow benched heads, balanced crank.

So this keeps the car as a 'family project' as well.

Now my question.....who's done power builds of a 401 nailhead. We'll be punching it to something near the 425 range. I know the TH400 will be fine and we'll beef it up when we rebuild it. But I dont know about the driveshaft and rear end. has anyone needed to beef them up before???

[1965rivgs]

The driveline will be fine but I would be careful about boring the block. Only bore the block as far as is necessary. The few extra cubes you will pick up by boring close to the water jackets is not worth the risk/potential downside. A few extra horsepower in such a heavy car wont make much difference, just my opinion,

Tom Mooney

[RivNut]

The 425 has a 1/8" (0.125") larger bore than the 401. Boring even 0.060 is risky in a nailhead - besides, they run hot if bored too far. Do as Tom says, only bore enough to clean up and make the cylinders round again. Besides, if you go 0.010 or 0.020 over the first time, there's enough room to go 0.030 or 0.040 over the second time. Before you do any boring, make sure you can find the pistons and rings you'll need. Then bore to fit the pistons.

The rear end is a 14 bolt 9-3/8" unit. Don't worry about it.

There are some thing you can do to make sure you get the most out of what you have. I'd suggest that you go to www.v8buick.com and check out some of the threads on engine builds.

Ed

Edited September 7, 2012 by RivNut (see edit history)

[alini]

Thanks for the tips guys. Our goal is streetable, reliable power. We arent gonna go paperthin on the walls, our biggest gains should be in the heads. They dont flow well at all from the box, so thats where we are focusing the most attention

[RivNut]

It takes a ton of work for any significant gains on the heads. You can get quite a bit by polishing and port matching. Another 15 - 20% by going whole hog. The extra time and the dangers that are incurred for that last 20% aren't worth it, especially if you've never done one of these particular heads before. If you're going whole hog, you'd best have a coupled of extra sets of heads to fall back on. One thing you need to be adamant about is NOT putting hardened seats in the heads. 1) too close to the water jacket and you can ruin the head in a heart beat, 2) Buick cast their iron with enough nickle in it so you don't have to worry about it. Don't let anyone talk you into it. If your son needs to learn how to do it for class, come up with some old chevy small block heads and have him practice on them.

Ed

PS - Gregg Gessler is the guru of nailhead heads. The following is from his website:

Quote LEVEL 3 - Street Performance $2,199.00 These heads give you the best “bang for your buck”. Because intake port velocity is kept very high, these Level 3 heads are highly recommended for heavy cars with mild gearing. Tom Kelly installed a set of these heads on his 1966 Buick GS -Tom picked up 4 tenths in the ¼ mile with these heads.

- Lot of dough for 4 tenths of a second.:eek:

Edited September 7, 2012 by RivNut (see edit history)

[alini]

He is already doing a 305 and a 302 block as we speak. By the time he gets the nailhead he will have a few months of constant work behind him, and with the instructors around I have faith it will turn out fine. He already has completed the block class, but the time we get to port and polish he will have 6 months into the 9 month head course. My son is motivated about doing the work and has pride in his workmanship, has patience (like his dad) and knows this is going to be shown off as 'His engine' so it will be fine