For those who've done the LS1 Swap

[bwilli2]

I'm putting in an LS1 into my 51.

And as a starting point... how far back from the end of the frame rails did you put your motor mounts? The engine I have has the Chevy Small Block adapters installed, but either way.

I know the only way to be sure is to put the cab on, but if I can get in the infield of the ball park before I do that, that'd be great.

Thanks in advance for any info.

[Gabbyp]

I am planning to put a LS in my 52 which has a No-Limit front end. The cab is off the frame. Originally it had a 327/turbo350 installed. The transmission crossmember is from Chassis Engineering and is a direct bolt in of the original X member. This placed the 327 engine so that there was no interference between the back of the engine and cab. I will bolt the T350 to the LS block and bolt the transmission to the X member which will place the motor mounts and where they fall in the frame and then weld the motor mounts to the frame. I can later make or buy a different trans X member for what ever trans I will use. I think this might help if you work from a known point rather than just measuring from the front of the frame.

[Kid]

you already know that putting cab on & checking YOUR clearances is your best bet to avoid wasting fab time & materials. Don't forget the trans fill tube, & the fender supports too.

[yossarian19]

I put my engine cross member centerline at about 29" back from the end of the frame.
Be aware that you have four or five real obstacles here
1. The engine must be high enough that the crank pulley clears the factory front cross member.
2. The original trans cross member can *just* be cleared but your output shaft will point too high up. So the trans cross member has to go. I'm using a 57 I-6 & 4 speed truck converting to Vortec & 4L60E as reference here.
3. The truck style oil pan, if used, will be 3/4" or so above your stock tie rod if you put the motor just about anywhere. You can flip the tie rod under the steering arms to gain a little, but not a ton, of clearance.
3.5 - the F-body oil pan will give you limited clearance to the axle beam itself. Depending how hard you hit the bumpstops, you could probably contact the oil pan. You'd have to work at it though.
4. If you don't mind having the rear of the motor not serviceable OR you work sheet metal well enough to massage the firewall and get clearance, you can avoid #3 by pushing the motor another 3" back or so. Otherwise, you need to leave yourself space behind the motor so you can get to things like oil pressure senders, bell housing bolts, etc.
5. Fan clearance. You need a radiator and a fan ahead of the motor, so you can't be too far forward.

Using the CPP LS1 mount kit, I mounted the engine 27" back (frame rail's tip to leading edge of mounting plate) & as high as I could get it in the frame rail. The rectangular mounting plates were turned lengthwise with the frame to get it a little higher. Not much steering clearance but everything else is cake.

[toeffer]

To many variables for fabbing based on measurements. Heres mine! Good luck with your build!

[bwilli2]

Originally Posted by yossarian19

I put my engine cross member centerline at about 29" back from the end of the frame.
Be aware that you have four or five real obstacles here
1. The engine must be high enough that the crank pulley clears the factory front cross member.
2. The original trans cross member can *just* be cleared but your output shaft will point too high up. So the trans cross member has to go. I'm using a 57 I-6 & 4 speed truck converting to Vortec & 4L60E as reference here.
3. The truck style oil pan, if used, will be 3/4" or so above your stock tie rod if you put the motor just about anywhere. You can flip the tie rod under the steering arms to gain a little, but not a ton, of clearance.
3.5 - the F-body oil pan will give you limited clearance to the axle beam itself. Depending how hard you hit the bumpstops, you could probably contact the oil pan. You'd have to work at it though.
4. If you don't mind having the rear of the motor not serviceable OR you work sheet metal well enough to massage the firewall and get clearance, you can avoid #3 by pushing the motor another 3" back or so. Otherwise, you need to leave yourself space behind the motor so you can get to things like oil pressure senders, bell housing bolts, etc.
5. Fan clearance. You need a radiator and a fan ahead of the motor, so you can't be too far forward.

Using the CPP LS1 mount kit, I mounted the engine 27" back (frame rail's tip to leading edge of mounting plate) & as high as I could get it in the frame rail. The rectangular mounting plates were turned lengthwise with the frame to get it a little higher. Not much steering clearance but everything else is cake.

Thanks for the details! Just looking for a 'rough' starting point, and that's a good one. I'll be putting an LS1 out of a 2001 Camaro, and a 4L60E as well, so I've been thinking on how to account for the issues you've brought up.

I've been looking at a lot of trucks that have the engine right up against the firewall with 4 to 6 inches of empty space between the fan and radiator and I'm wanting to avoid that. Like you said, I'd like to keep things some what serviceable with the engine in the truck and the cab on.

I'm already planning on my steering work arounds. I'm a bit away from that point, but I am finish welding the new front and rear suspension members, so I'm 'almost' there.

Thanks again!