I am rebuilding a 360 currently and was going to use the 390 crank swap, Since they are the same block. My question is i have seen many people going with a 427 stroker crank when rebuilding the 390. Can I do the same with the 360? Deck clearance? Will the 360 heads work? I know these 360-390 questions probably get asked alot but sorry, one more time. Thanks in advance. D
The 390/360 blocks are the same. Depending on what 360 pistons you have they should work with the 390 crank. If they are low comp truck pistons they should be good. You'll need the short FE rods. What's the casting number on the heads? It's between the center two spark plugs....
It depends on what you are doing with the engine, the 427 crank will be costly. You can go with a 428 crank with a 390 bore, works out to a 410. But with the 428 crank, it has to be externaly balanced and the 427 may also, not sure. You can build a 390 out of your 360 real ez and still get alot of horsepower for less money. Just my $.02 worth.
FWIW the 390 and 427 both have the same stroke 3.78. The 427 cast iron cranks are basicly the same as the 390. There were a few exceptions with the early grooved cranks. Of cource the forged steel 427 cranks would be more expensive but comparable in price to the 3.98 stroke 428 iron cranks these days. If you use a 390/427 crank it will be internally balanced and a 428 crank external.
The casting number on the heads is 203. I will also need to bore my cylinders so I was looking into some oversized pistons. I believe from other things Ive read I will need shorter rods, but you may be right because its a real dog. 1976. Thanks in advance.
360 Bore X Stroke: 4.05 X 3.5
390 Bore X Stroke: 4.05 X 3.78
427 Bore X Stroke: 4.23 X 3.78
428 Bore X Stroke: 4.13 X 3.98
As you can tell from this info it is real easy to change yor 360 into a 390 just buy changing the crank and rods. It is true what is said in the above posts about the balance situation but if I were you I could select what combonation I wanted, including oversized pistons if you are going to bore your block, and get the whole lot internally balanced by a reputable shop. Remember oversized pistons are going to be heavier because they are bigger and this will upset the factory balace job. Now if you want to go to yet more displacement you can go the 428 crank route. You can get the factory crank or buy a new SCAT crank in 3 different stokes. 3.98 (stock 428), 4.125 and 4.250. The latter 2 will require the use of aftermarket rods and pistons as the big end journal size is standard Big Block C@#v.
Good idea but IUA cranks are going for BIG bucks these days. The last I saw went for over $1000. SCJ balancers are $300 and up depending on if they look like swiss cheese or not. The std IU,IUB 428CJ cranks can be found for $300 and up. AI and A2 balancers for $20 in great shape with no cracking in the rubber. G.