im pretty sure the answer is 'yes' but ill ask those of you who are far more knowledgeable than I.

i have a 400 block sittin around that i planned to use for my car. is it bad that i cant use a roller cam? is it bad that id have to use a 2 piece rear main seal? those are really the only problems i see with building a 406. are there others and how much of an issue are the 2 i listed?
this is all way in the future, but id like to start planning.
thanks

 

Uh - you can use a roller cam...they have retrofit rockers,lifters and cams for 400's, they're just d*mn expensive (around 600 bucks). No problem really with a 2 piece seal either. GM made em for years and years.

The biggest concern is whether you'll get it internally balanced, or keep it stock externally balanced. You'll need to run a 400 flywheel and balancer if going external. Try a search - tons of good info!

 

People drove around SBCs for 30 some-odd years with 2-piece rear main seals, including myself, so it can't be too bad. I wouldn't let it scare me off from cubic inches.

I have the early roller systm in my 400, commonly known nowadays as the "retrofit" roller system. Works fine. Again, it's been working fine for decades, since long before the factory's engineering intern sodomized the whole concept.

Think of it as a 400. not a 406. You're not building some special non-stock combo, you're merely maintaining a used block.

 

for every "problem" you mentioned, theres a solution.

you can run a roller cam... you just need diff lifters and shorter pushrods.

you can buy a $60(or less) flexplate if you have a auto and you're all set.

if you have a manual, its a tad more costly... you either have to have a flywheel machined for the bolt pattern, the external balance, or both. they do make a bolt on behind the plate weight... but that seems kinda "iffy" to me... i havent ever heard of it until Tom400CFI (i think) said somthing about one.....


really they arnt issues as much as expences....