[camaroboy1991]

ok i really know nothin about building motors but i'm trying to learn but i was wondering if i can use a balancer and fly wheel from a 305 for my 406 i'm tryin to build a low budget race motor but i'm running out of money after buying all my forged parts and i have a 305 layin around and many extra 305 parts and i was wondering what all i could use off it mainly the fly wheel and balancer is it possible or practical? i also have rod bearings and main bearings and most of a rebuild kit for the 305 and when i look everything up everythings listed for all sbc's does this mean i can use all the same stuff i have?

[Quarter Flash]

The flywheel and damper will not work. The rings will not work. I doubt the bearings will work, but not positive. The bore size and cyl head port size will prevent those two gaskets from working on a 400 with 400 heads. 305 heads are too anemic for a 400.

Bob

[Henry Highrise]

400's are externally balanced so the flywheel and damper will not work ....the 305 is internally balanced.

[camaroboy1991]

i know the piston rings won't work it's way diffrent bore sizes i bought those when i bought my pistons but a while back i bought main bearings and rod bearings for the 305 and when i look up bearings for the 400 they all say sbc 283-400 so whille the bearings work or are they hopeless too and i'm guessing the pulley's will work for the 400 cause they all say sbc 283-400 also but then again as i said earlier i know nothing about building motors i'm just tryin to learn

[Quarter Flash]

I believe (99% sure) the crank journals on a 400 are larger than on a 305.

[camaroboy1991]

alright it looks like i'm back lookin for new parts but thanks for the help everyone you guys help me learn more and more everyday lol maybe in about 5 years i'll kinda know what i'm doing

[Blazin72]

Originally Posted by Quarter Flash

I believe (99% sure) the crank journals on a 400 are larger than on a 305.

The crank journals are indeed larger than the journals on a 305 (or a 350). The 400 is a bit of its own flavor within the small block family of engines. The block and heads have steam holes, the mains are larger than any other small block, it uses 5.565" rods and it's externally balanced (the only 86-earlier external balance SBC?)

Building engines can get expensive but it's better to wait and put it together right rather than slap something together and have it fail.

[baddbob]

The rod bearings are the same but the mains are different. You could use the balancer and flexplate off of the 305 but the whole package would need to be internally balanced with a lot of weight added (expensive). Your much better off buying the 400 balancer and flexplate. Also plan on having the rotating assembly balanced if you're buying different rods and pistons, etc. If these new parts don't weight close to what the originals did the balance will be off and you'll have vibrations and wear and parts breakage.