Engine Placement for LT1

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Sep 26, 2002
Yakima, WA
To start, I'm swapping a '95 Caprice LT1 350 into my '74 FJ40. I've already fabbed up my engine mounts, bellhousing mounts (I didn't want to use the AA style rear crossmember on the the t-case housing), and frame mounts, and welded them just where "I" want 'em.
If you're not entirely familiar with the s-belt routing on this particular LT1,.. to make a long story short, the a/c pump, which I am determined to keep for onboard air is right in front of the p-side motor mount and comes pretty darn close to the frame rail. My engine placement took into account clearance for my saginaw steering shaft, and keeping everything as low as I can for COG.

My question is: How much clearance is necessary/safe to keep engine components (a/c pump pulley) from hitting fixed objects (frame rail). I figure right now I have about 3/8"-1/2", but that can be adjusted or shimmed to give me more. Just how much IS necessary??

I really do not think that you are going to be able to tell untill you get it out and flexed up. Personally, I would fail to the side of having the engine an inch higher in the bay, to be sure that this is not an issue over cutting it really close, and having to re-do it later.

I am currently setting up a '64-40 With a Ram Jet/TH350/Cruiser t-case and have been at it for a bit now, wanting to make damn sure that I cut once, weld once, and that the drivetrain is lined up, and not going to interfere with anything. I HATE rework...

Just to let you know, unless that A/C pump is some internally oiled unit that I have never heard of, you will not get more than a year of light use out of it before it bites the dust. Even with an inline oiler. Might not be worth it.
IMO, for an onboard air compressor to pay for itself, it only needs to work the first time, when you need it,... it's not going to be used anywhere but on the trail, so that may be 12 times a year +/-. Another issue is that it is a serpentine belt system, and with the current component clearances, the max difference in delete pulley radius is not much more than 1/4", if any.
My thought process figured that I'd mount the engine as low as I feasably could,... it can always be shimmed up,... much more involved with lowering it.
I just wanted to bounce my thought process out there, as I haven't read or heard anything about min clearance of this type of moving part.

Thanks for your replies. :D
I would think it should somewhat depend on the type of motormount used. Some are more firm than others. The stock mounts from chev allow quite a bit of movement. Some of the aftermarket mounts are downright stiff. What do you have?
I am using brackets I fabbed up from scratch everywhere (engine, bellhousing, and frame). I am using an older style cast iron bellhousing that has 1/2" tapped holes, so I can more-or-less keep the same kind of idea Toyota had mounting the more solid part of the drivetrain. The mounts ate the later 2F style, and the bellhousing mount bushings are being reused in the rear as well.

Here's a couple pics I just took,... excuse the mess!!!
Now I hope these work!!
And another...
It's been too long since I messed with the 2F type mounts but it looks like you're on the right track. I have a hair less clearance on my steering shaft/steering pump side and haven't had any trouble using the AA mounts.
One of my buddies runs a motor like that in his J**P. Rediculous on the sand dunes. WWEEEEEHHAAAAAAA!!!

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