LS Motor into Which Vehicle?

**98 Formula FB** · 10-18-2019, 02:47 PM

So I've posted in a couple categories with thoughts in a couple different directions regarding my username vehicle that's sitting wrecked in my backyard (my son's).

I cleaned the leaves out of the engine compartment and drove it around the block the other day, and it really runs good.

If I buy it back from him (it was originally mine), I have 2 vehicles that I'd consider swapping the motor into - a '93 Caprice, or an '89 GMC C1500 with a 5-speed.

I like both of them. I bought the car as an engine donor for the truck, because it blackens and goes through oil quickly (covered in another post), but I've been driving it for nearly 2 years and put over 10k on it.

The car is nice to drive and floats down the road as it were, but it's underpowered - L03 5.0L with 2.56:1 rear gears.

I can envision the significant improvement that having a 300hp motor in either one of them would be. Would either be better than the other for reasons I don't know, like matching the LS to the 5-speed (harness issues, etc.?), or one or the other would have less mods to do for the crossmember or oil pan or what have you?

Neither one has a limited slip rear end, so I'm wondering if the F-body rear axle would swap over to one of them? I doubt it, but I'll ask. What about the guts of the gears and that?

If I go with the truck I'm done. I save the 4.3L block for my boat in case I ever need it, and I live with the car the way it is. If I go with the car, my truck still needs work (if the oil thing is improvable with head work, it's still just a 4.3), or I've got to do another swap - the 5.0L into the truck.

Several questions here maybe somebody has some thoughts on.

Oh, the Caprice has a 700R-4 I believe, and the FB is a 4L60E(?) Would that factor into the decision at all? I've also got an older GMC with a THM400 that's getting a little tired (slips outta D sometimes when cold, but shifts good yet) that I may want to use one of the "extra" transmissions for...

**98 Formula FB** · 10-18-2019, 03:04 PM

Sorry about the duplicate posts... I made some edits and that's what happened. Don't know how to delete them.

**98 Formula FB** · 10-19-2019, 06:00 PM

Well, interestingly enough, I had an impaired guy turn right in front of me last night and he didn't make it past the right front of my car. I was going 45, but hit the brakes. Broken headlight, slightly damaged hood, fender and bumper cover. It was a pretty good hit, but I'm kinda surprised that the bumper doesn't seem displaced at all. Stout car.

That doesn't really help the decision one way or another though. I'll see what his insurance says I guess, like if they try to total it out or what have you.

**98TransAmWs-6** · 10-20-2019, 07:51 PM

The caprice would be easier most likely to swap the motor on. The 700r4 is essentially the same as the 4l60e except that it is not controlled by a computer, it is controlled by a TV cable.

**98 Formula FB** · 10-21-2019, 04:22 PM

Ok, yeah the simplicity thing would be important to me, as I'd probably be fortunate to ever get a project like this done.

He just bought a pretty nice low miles '87 Corvette today with some of his Army bonus $, so I'm thinking he's gonna be less and less interested in trying to fix his FB. Even though that woulda toasted a 'vette of that era I'd imagine. I'll just hafta see.

**98TransAmWs-6** · 10-22-2019, 06:12 AM

Originally Posted by 98 Formula FB

Ok, yeah the simplicity thing would be important to me, as I'd probably be fortunate to ever get a project like this done.

He just bought a pretty nice low miles '87 Corvette today with some of his Army bonus $, so I'm thinking he's gonna be less and less interested in trying to fix his FB. Even though that woulda toasted a 'vette of that era I'd imagine. I'll just hafta see.

I've had an 85 vette and have a 98 trans am and yeah the vette would definitely lose stock for stock.

***SMWS6TA*** · 10-22-2019, 07:16 AM

Not if he striped the C4 down and made it a Vette cart as well as put a 383 stroker etc.....

**98TransAmWs-6** · 10-22-2019, 07:35 AM

Originally Posted by SMWS6TA

Not if he striped the C4 down and made it a Vette cart as well as put a 383 stroker etc.....

That's why I said stock for stock 😂

**98 Formula FB** · 10-23-2019, 03:09 PM

I had the Firebird to the track once the first year I had it (2013?), and ran a 13.99 @ 101mph on my first try. That was w/o a good solid launch - I limited the burnout on accounta I didn't want to overstress anything holding the brakes. That was also with the stock baffled air cleaner box thing. I changed to an SLP later.

I looked up the '87 'Vette #s, and I think it was 15-something at 93mph or so. He said it doesn't feel underpowered though. Standard gears were 2.59:1 or 3.07:1 as an option according to the info I read (@ howstuffworks?). Pretty high for a sports car...

**98TransAmWs-6** · 10-29-2019, 01:14 PM

Weird from what I found the 87 is slower than the 85 I had. The 85 could do a quarter in 14.1 regularly.

**98 Formula FB** · 10-10-2020, 06:23 PM

So the wrecked Firebird's been mine again for a while now. The Caprice was totalled, but I bought it back, fixed it (functionally; it's still cosmetically flawed) and am still driving it a lot, and the '89 GMC very little.

I actually rigged up some front turn signals and drove the FB for a week or two after I tagged and insured it (temporarily). It's got a coolant leak from the water pump area, so I think that may have gotten bumped in the wreck although nothing's touching it now.

Still have the dilemma about which vehicle to put the LS into, if I ever get around to it. I'd kinda like to keep the FB motor and trans together, but my truck's a 5-speed... But I hate to take the running and driving perfectly fine Caprice outta service on a swap job that may never see completion. And it's even less pretty now than it was what with the F/E rash.

Will that F-body rear end go under a B-body? I haven't tried measuring them yet. I'm pretty sure it won't go under the truck. It would be nice to swap that too if possible.

**98 Formula FB** · 10-10-2020, 06:26 PM

Originally Posted by 98 Formula FB

Well, interestingly enough, I had an impaired guy turn right in front of me last night and he didn't make it past the right front of my car. I was going 45, but hit the brakes. Broken headlight, slightly damaged hood, fender and bumper cover. It was a pretty good hit, but I'm kinda surprised that the bumper doesn't seem displaced at all. Stout car.

That doesn't really help the decision one way or another though. I'll see what his insurance says I guess, like if they try to total it out or what have you.

It was the Caprice that took that hit. FB was already wrecked.