Deciding on replacement intake (318, details in post)

junkyardhero said
having built the fabled 400hp 318 (twice, natch) your make or break is going to be the heads. to note, that 400 was just barely and everything has to be dress-right-dress to get there. and i honestly don't know if the air gap will do it over the single plane. i can tell you that i took the single plane off and wound up putting on an airgap the second time (it wasn't available the first time i built one) and that made the car much more driveable.

anyway, onto what you've got cooking. if you're not looking to spend a ton of dough or re-engineer the whole enchartio, i'd say you probably have enough cam to get there. those sealed power slugs aren't a bazillion miles in the hole and are up to the task.

so, heads. either you work the F out of your 915's or... flip for some eddy's, speedmaster or trick flow. given your locale i think by the time you splash the pot for some magnum heads you're pounds ahead just biting the bullet and getting something aftermarket that'll support your cam (or the air flow requirement) needed to hit the number without a bunch of additional work.

with that combo, plus an airgap and 750 i say you'll tickle just shy of 400

I was looking at the cost of heads on the Summit app this afternoon. I did notice that Trickflow are quoting higher flow rates than Edelbrock so could be more of a goer straight out of the box?

Flipped the block and pulled #1 piston and rod this evening, noticed the big end and the big end bearings are pretty scratched up, the crank is also .010 undersized. Rods are the usual 318 items the part no. now escapes me but there have been plenty of posts discussing them (not bushed at the little end). The crank has been ground, I can’t find any numbers of meaning, 616 on the end of a counterweight, 5389 on the side of the counterweight at the balancer end but nothing else.

This has given me some uncertainty and perhaps increased the shopping list.

Hopefully tmw I’ll get the remainder out and have a good look at the bores.

BTW, I’m grateful for everyone’s input and patience - the continual ‘oh and today I found….’ is a bit tedious but I don’t get much time outside of work on weekdays.