cam383

iTrader: (4)

Hey guys have an engine swap question.

I have a chance to buy a 307 motor that was lightly used for circle track. I can get it for $200 so I figure it would be a nice cheap upgrade to my tired 305. My questions would be:

1. Will it bolt up to a 700R4 or am I looking at swapping tranny as well?

2. Can a TPI or TBI be setup on it, am I stuck with carb or do I need to swap heads too?

3. Can a serpentine setup be put on there or does it have to be V-belt?

4. Will sensors go in with no problem?

I don't know much about the 307 motors and didn't find much info searching so I was hoping someone out there might know.

five7kid

iTrader: (14)

The 307 is nothing more than your run-of-the-mill small block Chevy. It has the bore of the 283 and stroke of the 327, meaning the bore is larger and the stroke shorter than the 305. Also meaning there is no difference with regard to bolting up the transmission.

The dipstick will be on the driver's side, which gets in the way of stock exhaust manifolds. If you have or will be installing headers, no problem.

The crank/block are of the 2-piece rear main seal variety. The flexplate/flywheel bolt pattern is different than the '86-up 1-piece rear main seal, so you'll need a flexplate/flywheel for the '83-'85 application f-body.

Serpentine bolt-up is a matter of what heads are on it. Something tells me a circle track engine won't have stock 307 (aka, "boat anchor") heads on it. Bolt holes on the ends of the heads is what matters, if they're there, no problem. If they aren't, big problem (you can't just drill and tap bolt holes in non-bolt-hole heads - there isn't enough material, and the "pad" isn't there). Be sure to use a serpentine water pump.

It's about a 99% proposition that the heads aren't of the '87-up intake bolt pattern. If you have TPI, put your 305 heads on the 307 (depending again upon what heads are on it now). If you have TBI, and you need different heads because of the serpentine issue, look for TPI heads. Regardless, heads are not a major factor in EFI vs. carb.

The only possible sensor issue would be if your car has an oil pressure sender above the oil filter. Older blocks didn't have that port.

EFI needs a friendly cam. I seriously doubt a circle track engine would have an EFI-friendly cam. Switch out the cam, and you won't have any problems.