TXjeepTJ

iTrader: (8)

UMI Performance GM A-Body LSX Engine Mounts 4008-R

These motors mounts say in the description that they fit the stock LS1 oil pan with no modification. I'm seeing many people not being able to run the F-body oil pan unmodified.. I plan on doing the swap this Friday and am wondering if I should have ordered an aftermarket pan..

from the description "Swapping an LS engine into a classic GM A-body is nothing new. UMI Performance LSX engine mounts allow the installation of an LS engine directly into your A-body. By retaining the proper angle of the engine, you keep your pinion angles/drivetrain operating smoothly. This is a good reason to get pre-engineered mounts for the swap instead of trying to make something work. These mounts place the engine in the factory location, but also give you the ability to relocate the engine rearward up to 3/4 in. or forward 1/4 in. UMI's LS engine mounts will bolt directly to your car's frame and the LS block without modifications. Their brackets have greasable polyurethane mounts to dampen vibration, but still provide a solid feel and eliminate the need for additional modification when using the LS1 oil pan. New premium mounting hardware is also included. Getting a quality set of mounts designed for your application will definitely make the swap a lot easier"

It will be running a 4L80E also. I read that you can't install the engine and transmission separately also??? You have to install the engine and transmission at the same time for this to work w/ the stock f-body oil pan?

Project GatTagO

iTrader: (7)

The best option for A-bodies and a 4L80e is the Holley 1" forward mount and the 302-2/3 oil pan.

Andrew

1964SS

iTrader: (1)

As Andrew said the Holley pan is the best fitment option. I do not have experience with the UMI kit, but I can tell you that the F-body pan will not fit in the stock bell-housing location without modifying the pan or the cross-member. I have seen people fit the F-body pan in an A-body without any modification, but the engine is extremely close to the firewall to do so which means that big 4L80e will then give you more troubles with the trans tunnel size. I am using the f-body pan with a notched crossmember in my 64.

TXjeepTJ

iTrader: (8)

According to UMI, their mounts place the engine in the exact location the SBC/BBC sits - and since the 4L80E is the new version of the TH400, I'm hoping it works out..

I will report back. Will be doing the swap this weekend, will hopefully have the engine in Saturday

Toddoky

I can save you some grief with the engine/transmission combination you are wanting to install in your A-body. The LS engine block is 1.25" shorter than a SB Chevy and that length is all missing off of the back end of the engine, which means you can move the engine/trans mating plane forward in the car by 1.25" when installing an LS engine in place of a SB and the position of the cylinder heads and front of the engine will remain unchanged.

The 4L80 is longer than a TH400 and that extra length is going to cause the rear top of the transmission case to experience interference with the pinched down area of your tunnel and require you to lower the tailshaft of the transmission to clear it, resulting in poor U-joint operating angles.

You can of course cut out your tunnel over the transmission and rebuild it to permit desirable U-joint working angles to be obtained, or you can take the easier route of moving the eng/trans mating plane forward by the previously mentioned 1.25" and everything will fall into place with no cutting/rebuilding of the floor required as long as you are using engine mounting brackets and a transmission crossmember that are designed to work together to provide the engine height/inclination angle required to produce such results.

TXjeepTJ

iTrader: (8)

So I guess hopefully I can move the engine forward 1.25" from the SBC location with the F-body oil pan

DailyGTO

So every car is a little different but I doubt the "factory SBC" location will work with a stock F body pan and stock crossmember.

I just went through this on my 66, the engine would drop in, but the pan was resting on the crossmember. This was an F body pan, ICT billet plates/Anchor mounts to put the bell housing at the stock SBC location (I am running the old clutch linkage with a muncie so it has to be in that location). I have about 1 inch of room from the upper side bellhousing bolts to the firewall, so I dont see how people could move the engine back much more. Now if the engine was higher it might work. I ended up with the holley 302-3 which fits very nice.

https://ls1tech.com/forums/conversio...-runs-vid.html

Toddoky

The F-body pan won't clear the engine crossmember at that position, but you could get it to fit by notching the back side of the crossmember. The sumps of the Holley 302-2 and 302-3 oil pans are few inches shorter in length than the sump of the F-body pan and they do clear the crossmember at that engine position.

TXjeepTJ

iTrader: (8)

Alright everybody, verdict is in:

The F-body oil pan with UMI 4008-R motor mounts, with the engine set forward as far as it will go, WILL FIT (with this Chevelle atleast) a 4L80E with a correct pinion angle.

This is not without mentioning that we hammered the S**** out of the tunnel, but 30 minutes of hammering/checking transmission angle/clearance was well worth not spending the $300+ on an oil pan lol

Toddoky

Glad that worked out for you. You've discovered first hand the difference fore-aft engine position makes when fitting an LS in an A-body. When you move the engine/trans mating plane forward by 1.25", you don't have to do any hammering of the body to fit a 4L80 transmission in these cars, but anything short of that you will to obtain desirable U-joint angles.

TXjeepTJ

iTrader: (8)

I think running it the way we did saved a lot of heartache, not only for the cost of the oil pan, but because the engine has full F-body accessories - I read that the F-body alternator wouldn't fit (would hit the steering box), which would have been true if it were to use the muscle car oil pan and moved it forward.

So if anyone ends up wanting to run F-body oil pan and accessories, UMI motor mounts are a good choice, just know you'll need to really hammer at the trans tunnel.

Thanks for everyone's help

Toddoky

Yes that's correct, the F-body accessories won't fit with the eng/trans mating plane moved forward and is the reason Hooker offers both forward bias and rear bias engine brackets for the A-body. For someone using an old school Powerglide TH350, TH400 or 2004R transmission, the rear bias engine brackets work fine and allow more choices for accessory drive configuration. For those using a 4L60 or 4L80 transmission, the forward brackets offer hammer-free installation with some limitations regard accessory drive compatibility.

TXjeepTJ

iTrader: (8)

Good info! Hopefully this thread helps some people out in the future

1964SS

iTrader: (1)

You mean the forward mounting holes correct? The motor has to be set back as far as possible to fit an F-body pan not forward.

TXjeepTJ

iTrader: (8)

For the UMI motor mounts, the max position forward is the closest you can get the Fbody oil pan to the crossmember. When they said they engineered these motor mounts around the LS1 oil pan, they weren't joking lol it is literally 1/4" away from the crossmember - with the engine at it's forward most position.

Pretty much, if you use the UMI motor mounts, and you get the Holley 302 oil pan or whatever for the extra clearance, you are wasting your money, because you will not be able to take advantage of the extra 1.5" of clearance with these motor mounts. The furthest these mounts allow the engine to go forward is to allow f-body pan to fit. They can slide rearward (which generates even more trans tunnel problems). Great question, hopefully someone sees this before ordering UMI mounts w/ modded oil pan.