pontiac block

[streetbird]

Ive got a 69 350 pontiac block.
My question is very simple, can I overbore it and put 400 pistons in it?
I've read thad the 350 and the 400 had the same stroke, same journal size and deck height.
So basicaly the 400 is a big bore 350?

[takid455]

Watch your wall thickness. At 0.245 piston bore difference, you will be in the water jackets.

Pontiac blocks are all the same dimensionally 326-455 but internals differ.

You could put 400 pistons in a 350 but will more than likely need to be sleeved. I would start w/ a 400 block. I have a pair if you are interested. Shipping over the boarder would be costly though.

Wallace racing has lots of quick reference facts
http://www.wallaceracing.com/boresizes.htm

[streetbird]

ok thanks for the info

[Ummgawa]

I've heard of a 400 block with a 455 crank turned down to fit. Instant stroker.

[Nativefx]

Originally Posted by takid455

Watch your wall thickness. At 0.245 piston bore difference, you will be in the water jackets.

Pontiac blocks are all the same dimensionally 326-455 but internals differ.

You could put 400 pistons in a 350 but will more than likely need to be sleeved. I would start w/ a 400 block. I have a pair if you are interested. Shipping over the boarder would be costly though.

Wallace racing has lots of quick reference facts
http://www.wallaceracing.com/boresizes.htm

Takid455, I might be interested in a 400 block to build a motor for my 69 Firebird. Can you PM me with info about the blocks you have and how much your asking?

[72blackbird]

X2. A no.481988 or earlier 979xxxx 400 block and stroker kit is a great way to get big cubes from a Poncho V-8. Add 320+ cfm ported aluminum heads and a roller cam to a 400/461 stroker and 600 hp/600 lb.-ft. on pump gas is typical. Poncho engines are also known for torque, so that 600 lb.ft. comes in early, around 2500 rpm depending on the cam. Even the 350P can be stroked with a 4.00" crank, 6.8 BBC rods and custom pistons, but the smaller bore of the 350P limit it's HP potential- the best build for the money in terms of HP is the 400/461 combo.

If you can find a 455 block, don't ignore those either- they have a larger 3.25" main journal, but are still in high demand because they can also handle 600 hp and come stock with a 4.21" stroke crank. The 400/461 stroker combo does have less friction thanks to it's 3.00" mains, but there are plenty of them out there built that make similar power to any 461.

Geno

[WSSix]

Originally Posted by Ummgawa

I've heard of a 400 block with a 455 crank turned down to fit. Instant stroker.

That creates a 440 if my memory isn't failing me. It's a great combination.

[T_Raven]

Pontiac stroker kits have gotten pretty affordable. Cheap enough there's no reason to mess with a stock 400 crank and rods when trying to make power.

Butler Performance has all you could need for a Pontiac build.