i have a 1966 352 in my truck and it it is shot, so i was going to buy a 1968 rebuilt 390 long block and drop that in! i guess what i need to know is can i swap my flywheel , harmonic balancer, and 4bbl intake from the 352 to the 390? also when i was looking at the 390 long blocks, they were asking about a 5/8 crank bolt or a 3/4crank bolt?!

 

Anything you want to swap from the 352 will bolt right up to the 390 longblock. They are both internally balanced. I'm not sure what the "crank bolt" thing is about.

 

I guess what they are asking about the crank bolt is the bolt that hold the harmonic balancer on? Just want to know if I am right about that?

 

also what do they mean when they say the 68 390 does not have intake/exhaust crossovers in the heads? does my 352 have these?

 

They are most likely referring to the difference between FE and FT. The FE's brother the FT used in industrial applications have a different exhaust crossover. I know at some point, 1970 i think, they switched from a 3 bolt to a 4 bolt harmonic balancer. I'm sure the bolts are different, maybe this is what they are referring to.

 

thanks sleepy! i know my 352 has the 3 bolt front pulley, and then the front bolt is the 5/8!

 

Glad to help. Good luck getting it back together!

 

According to the interchange book I have, all the bottom end hardware such as the harmonic balancer and flex plate should interchange. The only ones that are different are the 410 and 428 which are externally balanced so the flex plate and sometimes the harmonic balancer are weighted. As far as the intake manifold goes, I didn't see anything conclusive but the book I have implies that it would be interchangeable but you might want to whip out a tape measure and compare the port sizes.

 

you mean 428*, the 427 is internally balanced. And yes all FE intakes aside from certain 427 intakes will interchange.
Basically the 427 is the only one that has parts that cannot swap onto the others.

 

Your absolutely correct, sorry about the typo, 410 and 428 are the externally balanced ones. Thank you for catching that, I would hate to get off on the wrong foot here by giving bad info seeing as I'm brand new here

 

no problem. fair warning though, some people (if you've read any past threads you probly know who) will not be so friendly with a correction. Thats why I try and double check anything I put on here, just to make sure I don't get flamed. LoL

Late night on FTE eh?

 

Ya, no kidding. As I like to say 'some peoples kids' And ya, I'm always up super late with my job.

 

hey guys, you are awesome! thanks so much for all the help! i just wanna drive the truck when it gets nice here and i think the wife is getting annoyed with this project! lol

 

I believe that the 390 uses a bigger clutch than the 352 so if you use the 352 flywheel you will need a clutch & pressure plate for a 352/360.I don't know whether or not the smaller clutch will hold up on a 390.

 

Some people choose to block the crossover ports. When I have time, I'll put up some pics I've taken of early and late heads. They all have the crossover ports.

When you have time, look on top of the intake for some letters and numbers that are cast in. Tell us what you find.