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Big block swap issues

bayou blazer

1/2 ton status
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Jul 16, 2004
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I thought this would be an easy swap with no real issues. I just found one. It seems that the oil pan is hitting the crossmember. It is just resting on it. It seems that the engine is sitting too low and or too far forward. The old engine was 350/TH350 and now is Gen VI 502/SM465. I know that many of you have done the big block swap. Any ideas? Could use some ideas.
Thanks.
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Looks like you've got the engine bolted in. Just notch the crossmember and forget about it, or make a new crossmember so you can drop the oil pan in the future if you ever need to.
 
or find a truck that used to have a big block in it, and just rob that one, (ok dont rob it but get it.)
 
Has more to do with the oil pan shape. Not all oil pans are created equal.
 
The oil pan rested on the crossmember on my 74. I plan to build some spacers to fit between the crossmember and motor mounts.
 
Hmm, that is weird, I put a 454 in my old truck and didn't have any issues. Motor was out of another truck, so had the bigger pan. I don't even think I got new motor mounts, stock ones off the 350. I had a 454 in my 78 Malibu and didn't change the pan on that, and that was out of a truck too. Are those BBC motor mounts?? Could use a spacer under the mounts, that would lift it off the crossmember.
 
Like b454rat, I question the motor mounts. I'm not sure if there's a difference between sbc and bbc actual mounts but the "bells" are different (pretty sure the difference is they're taller).
 
Thanks for all the help. I pulled the engine mounts off of my 350. I bought the truck from a friend that had recently put that 350 in so I don't know if the mounts are original to the truck. I had thought that BBC mounts would move the engine down in the frame. I don't need any help in that direction! I also put on a set of BBC headers and they were hitting the frame rail on the passenger side. It just seems that the engine is sitting too low in the frame.
 
Cracked mounts or crossmember will let the engine sag and is real common prior to about 1985.
 
wrong motor brackets...

Looks like the brackets bolted to the engine are 2wd truck or passenger car versions..4wd ones are 1" taller,between the block and thru-bolt hole...I see this happen often when a car engine is swapped in,and the original brackets dont get re-used..spacers between the the motor mounts and crossmember, or the engine bracket and block will work if you cant find the "right" 4wd style brackets to the motor..--you can find a 3/16" thick spacer factory on the drivers side mount between the block and bracket of a"G" series van,or you could fab your own..a couple on each side will lift your motor up enough,since its not hitting that bad..I'd not cut the crossmember!..:crazy:
 
That seems to make sense. I have no idea where the engine came from. I will try to source out some mounts and get me more clearance. Thanks to all who helped.
 
If you use spacers between the block and engine bracket you will have to re-drill new holes in the frame for the motor mounts as the brackets will no longer bolt onto the motor mounts since the bolt spacing will be wider.
 
Another vote for the BBC bells being taller versions.
I have always had good luck with the 3/16" spacers and motor mounts fitting up real well - the slots have had enough room for the adjusted position.
HTH's Tom
 

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