Wanting to build a flat head V8 Ford for my A. With 3 Holley 94's, Navarro tri intake and heads, headers, Isky 3/4 race cam and a Mallory distributor. What kinda power could I get? Stock size valves and no relief. Its a street and strip build. More street.
Actually, compression and improved "quench" are both obtained by reworking the heads rather than changing pistons as is done with OHV engines. One should try to obtain around .050" over the piston in the combustion chamber. This is usually done by measuring the existing clearance over the piston using clay or foil balls, milling the heads to get a nominal .050", and then using a die grinder to clean up any spots with less than minimum clearance. This is probably the best thing to do to improve both performance and economy. Unless you are planning on an increase in displacement, three carbs may be too much. I also think that 40 hp at the rear wheels is a little optimistic for what you are planning.
If you're going to bore it and buy new pistons, why don't you go .125" over? It's a safe overbore (at least for 59's and 8BA's and will give you and engine of 258 ci (3 bigger than the vaunted Merc crank). The pistons and rings should cost just about the same as .030" over. And "flat tops"? You have been talking to too many OHV guys.
Domed pistons. Would it be ok with Navarro blower heads? Also, who offers a nice period correct 4-71 kit with the multi belt and gen relocation bracket?
Whoa! Now we're talkin' a whole different ball game. I was under the mistaken impression that this was gonna be kind of a low buck build. This is how to make power with a flathead, though.
Yep, you can make north of 300 hp if you follow Joe's ^^^^ recipe like @tubman said above. I can personally vouch for it and yes, I put my money where my mouth is. I bored .125 and went 8:1 CR, pruned 471, a ton of porting and 3 97's on a 8BA. I have posted the dyno pulls before, I'll have to look for them on my thread history. Like Joe, i made my dyno pulls with a 4 barrel Holley on the blower, I changed to progressive 97's afterward. Better make sure there is around $15,000 in your bank account. That way you will only have to charge a couple thousand on your credit card.
You can expect 120 to 130 hp at the flywheel with what you quoted for parts. Flat top pistons are for all out naturally aspirated race engines. They require special heads with no dome.
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