I just read that you can bore out a 307 to 4" and use std. 350 pistons.Can you? Is it reliable? Also are inline 250 pistons interchangeable with the 307? I would apreciate any help. I want to use what I have available,camelhump heads,'70 block,tarantula intake,old AFB.
with proper machining and an excellent corre, yes. easier to use a pre 74 350 block, better nickel content, better chance of it being within tolerance
That was an age old question with the 283s.....could you bore them enough to take the 327 pistons. It took a .125 overbore to get to 4", as does the 307. It all depends on the block, sometimes while casting the cores shifted slightly, and when bored, they hit the water jackets. Same is probably true with the 307.....you are taking a chance. They have sonic testing that they can do to see if your block will take it.
I think you have to use 327 pistons cause the stroke on 307/327 is the same (3.25"?) and the stroke on the 350 is something like 3.48" so you wouldn't end up with any compression.
or you could use small chamber (58cc) 305 heads, bump compression, new rings, good to go, if your lookin for the cheap route
I have a set of 305 HO heads and an intake too.I thought deck height was a concerne when swapping pistons and you could only use compatable pistons.
I agree with Fat Hack. As all 307 blocks are of the two bolt main type anyway, just find a garden variety 350 engine and use it. Remember, if you tell the machine shop that you want them to bore your 307 to 350 bore and they go through to the water jacket on the last hole, you still owe them for boring the block, even though it's scrap.
Hack's right. Actually best thing you can do is shorten the stroke and make a 283 out of it. You can buy a crank from eagle or scat or find the ever elusive 302 crank. If you want a 350 cores are cheap.
Well yea. The 307 is a trotline weight. Bad bore to stroke ratio. The 283 on the otherhand is a minnie powerhouse. Good revs, and snap. they respond well to being bored, and it doesn't take much cam and head work to make one breath. Unless you need one to move a bus or pull stumps you just can't go wrong with a short stroke mill.
Any good, respectable, honest shop would either talk you out of boring the 307 block that far, might offer to buy your 307 core (especially if you buy a 350 core from them) or would AT LEAST sonic check the 307 block **before** getting the block anywhere near the boring bar/ block machine. -Bigchief.
Is the 302 a 350 block and a 283 stroke crank? I never realized there are so many combos for sbc's, now I'm more confused than ever.
hot rod did a story about what size you get with x block and y crank, what rods to use, what pistons, rod length, etc...... 40 some combinations, not using a 400 block, can be useful.
A 302 is a 283 with a 4" bore. its actually 301 and change, we called 'em 301s before Chebby called 'em 302s. Chebby probably named 'em a 302 to compete for the market with Fords new 302. There were an awful lot of 283s way back when that got bored .125 or taken out to a 4" bore. It makes it a throw away block, or its your last overhaul, or at the very least the last time you bore that block unless you're boreing it to press sleeves into it. The sleeving it is iffy unless you're willing to run wet sleeves. Wret sleeves is not your best option, they don't always work out well.
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