Any issues with swapping from 396 to 454 HO in 67-72 Trucks?

[engineer_gregh]

I had my 402 rebuilt a couple of years ago and it was expensive. Machine shop costs are crazy high. I've often wondered if I wouldn't have been better off buying a crate big block myself. I went with headers and they sound great but if I had it to go over again I would have stuck with the stock manifolds. Does your truck have stock A/C? I believe that makes a difference in long vs short water pump and which valve covers you can use if you stay with the A6 compressor. Does the crate motor have the alternator on the drivers or passenger side of the block? I would think Summit or Jegs can answer a lot of these type questions. There are several board members here running 572's and so forth that are a wealth of information. Good luck and please keep us posted on the direction you take.

[hugger6933]

If the crate doesn't come with a flexplate/flywheel that is the only difference I can think of off hand between the two motors. Yes you should be able bolt the acc and water pump[new of course] on to the fatter rat. the motor won't quite make the full 425 with manifolds but you won't lose over 25 hp I would think by not using the pain in the rump headers. I've NEVER seen or even heard of a machine shop that pulls and does rebuilds. For the most part either it is a auto shop that can do that or a machine shop to do the rebuild. I think the crate motor is a smart plan that you should enjoy. Jim

[68 CRACKERBOX]

only big thing is I think you will hurt the valve of the truck by putting a 454 in place of the org. 402. 402's are worth a lot more than a 454.

[ss454conv]

I suggest you do a 454HO oil consumption search before you purchase. Unfortunately there are tons of posts to read on the subject.

[Valarius_Starchaser]

Originally Posted by ss454conv

I suggest you do a 454HO oil consumption search before you purchase. Unfortunately there are tons of posts to read on the subject.

I have seen and heard more recent engines having much less of a problem on top of that with it being a drop in and not a buy and build before he drives it would still be in the warranty I vote let her rip if you've got the green and the drive

PS: I have also never heard of a machine shop pulling an engine

[Jonlopes]

Originally Posted by Valarius_Starchaser

I have seen and heard more recent engines having much less of a problem on top of that with it being a drop in and not a buy and build before he drives it would still be in the warranty I vote let her rip if you've got the green and the drive

PS: I have also never heard of a machine shop pulling an engine

I read the same thing. I guess Chevy Performance pulled the engine in 2012 to re-do something in the manufacturing process and re-released.

[davischevy]

The only issue I have is I didn't go 454 while I had my 402 out.

Get the balanced flexplate for the 454.

[Jonlopes]

Originally Posted by engineer_gregh

I had my 402 rebuilt a couple of years ago and it was expensive. Machine shop costs are crazy high. I've often wondered if I wouldn't have been better off buying a crate big block myself. I went with headers and they sound great but if I had it to go over again I would have stuck with the stock manifolds. Does your truck have stock A/C? I believe that makes a difference in long vs short water pump and which valve covers you can use if you stay with the A6 compressor. Does the crate motor have the alternator on the drivers or passenger side of the block? I would think Summit or Jegs can answer a lot of these type questions. There are several board members here running 572's and so forth that are a wealth of information. Good luck and please keep us posted on the direction you take.

Yes the truck has AC and that is one of the reasons I am liking the 454HO because it is one of the only crate big blocks that have the short valve covers which are needed to clear my compressor.