Big cube 454 for fun
#11
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If you find some core shift, some machine shops, will offset the bore index if you desired. Meaning, if you find .300 on one side, and .230 on the other, they can offset the bores.
For what you're doing, I wouldn't worry about it. I'd prob go with a minimal bore thickness of around .200, unless you plan on spraying nitrous, or strapping a blower on it.
FWIW, on those old Mark IV 454 blocks, .100, or even .125 overbores, weren't unheard of back in the day. But the blocks varied alot, some could go, some couldnt. Just depended on the casting. Thats why ya gotta measure them all over the place to make sure you're casting is consistant.
I'm liking the idea of a 4.375 x 4.350 build (520ci). I think you could make a nice stump puller.
#12
I think it would be a fun and different project.
Funny you mentioned the trick flow heads, i dont think ive ever seen them on a marine engine, but do all the time on cars, wonder why that is?
Funny you mentioned the trick flow heads, i dont think ive ever seen them on a marine engine, but do all the time on cars, wonder why that is?
#13
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I don't know how they are since Summit Racing bought them out, but I know my head guy really likes their quality. He uses alot of them over the years. Mostly Fords, but some BBC ones as well. I've heard good things about them from other head guys as well.
If I didn't go with the EQ heads, I was looking at the aluminum RHS 320's as an option. They run about 500 a set cheaper than the AFR 325's bare (1500 a set). They come with Tungsten valve seats. The EQ's come with Powdered Metal. AFR's come with Ductile Iron. For marine engines, I myself, won't run ductile seats. They have been proven to simply not last long.
Last edited by MILD THUNDER; 02-10-2017 at 05:36 PM.
#15
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I played with that kind of overbore years ago in drag boat engines, and as stated the thickness were all over the place, have to have the block sonic tested and fine one thats thick, we ended up filling the blocks to make .125 work decent, but in reality, you would be better off with a better sealing .060 than a leaky .125
#17
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Dont the bow tie blocks have thicker walls, seems I read that you could bore it to coffee can size, dont see many around, must be low production, I know their pricey if you can find one.
#19
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They also made some bowtie race blocks, with billet caps, instead of the ductile iron. I believe the billet cap ones, were rated for 1200hp, where the ductile cap ones, were rated for like 800hp if I recall. According to GM's literature.