Hello Everyone,

I have a customer that is interested in a 434 sbc. 4.155 bore 4.000 stroke but you probably already know that. I am very inexperienced with stroking application. I have a part list together for the bottom-

4-400-4000-6000 scat crank
2-350-6000-2100 scat rods
Je piston p# 194339

I have a very good machine shop that I deal with but I want to get some input from you guys as-well. One thing is a will be going with a small base circle cam. I need to know all the areas to for clearance's or if there is a website or something with pictures to show all the areas to look at. I don't even know if this is possible for stock block. If someone could give me some guidance I am always trying to learn.

Thanks for your time...

Ive always heard you needed the raised cam blocks to use the 434 kits. I think the biggest is 420 but Im not sure.

Check here on this web site they have all you need to build those motors. You better have some deep pockets.

http://www.shafiroff.com/

It can be and is done with stock blocks. If your customer can swing it, would recommend upgrading the block to something like a Dart Little M block. The stock blocks are really not the best choice here.

As far as clearance issues, the best advice I can give is to mock-up your assy and mark were the block needs to be clearanced for the rods. Reassy and check--takes awhile, but needs to be done. Balance after this step.

On a side note----check the oil pan also before you install. Some pans wont clear.

You will need small base circle camshaft with this, no doubt!

Also make sure to check the rod to cam clearance,even with small-base circle,the rods will sometimes catch the cam

Chris Laarman
Ottawa Engine and Performance

Only 10% of the stock blocks will stand that much bore reliably with that much power. I found lots of 400s with undetecable voids in the cylinder wall. = bore them .030 and have an 1/8 inch hole through the wall, etc. so it had to be sleeved and hard-blocked. I would guess 10% at .030 over and 20 % at .060 over had at least one hole. Still have seen +.030 400s blow pieces the size of nickles or bigger right out of the cylinder walls.

Unless you spend 10 hours sonic checking a 400 block you will not find 80% of the voids. If you are going to build a stock block 400, just poke it .030 and keep your fingers crossed, in my opinion.

Yep, there's lots of them out there running fine.

Maybe I should talk him down on the stroke to keep it safer. What do ya think?? I knew that I would have to do the test for the block. man I have to sit down with him. I think the aftermarket block is out of the question.

some casting are that bad - jezzzz

Thanks for that website. I was just checking it and printed a couple pages of it. Prices seem hard to beat.

Contrary to popular belief, sonic checking a block only checks about a dozen strategic spots, not all the entire walls.

400s and lots of 350s are thin wall castings. Dont forget core shift! If you bore and there is no hole, you have no way of knowing if the wall is .005 thick or .150 thick in an undetected thin spot, or is it .060 in diameter or an inch in diameter.

Consider "hard-block" necessary on a 400 like you are building.