I am looking to do an LT1 swap into my IROC-Z this winter and I am wondering how difficult it is to do. Will it fit on the stock motor mounts of my L98? Will it work with a TH700r4 tranny? I know the A/C will have to be removed for clearance issues, but things like header space are of concern. I can get a corvette LT1 w/wiring harness for 2500 with about 70K miles on it and I am wondering if this is good, rather easy swap. When I say easy I mean that 90% of the things will bolt up in where the L98 was. I am considering this because it seems to be the cheapest mod to get the power output I wanted. I was initially planning AFR heads and a Mini-ram but it costs more than 2500 and would still choke out at 4500 rpm from what I've heard. if I am gonna lift the motor to install a cam ($250) I figured I might as well drop in an LT1 and get similar results for less money and have something a little fresher anyways.

 

The physical swap is easy. The motor is basically the same as any 350 as far as dimensions and internals, so your headers will bolt exactly the same way they dao now. You can keep AC but will have to notch the motor mounts to do it and make your own lines (not worth it IMHO). But the motor does use the motor mounts and you can use your 700-R4 without problems. You just have to go to Chevy and order a throttle cable plate for the '92-'93 LT1 cars cuz they have the provision for the TV cable.

Now here's some money saving advice for you. I've seen better deals than that for LT1 motors. Plus, you can't use corvette accessories in the thirdgen engine bay (the pulleys hit the steering box, I've tried). You can use the corvette LT1 (very little advantage over a 4th gen LT1) but you're going to have to get the 4th gen accessories and bracket anyway. What I would do in your spot is find a decent deal on a 4th gen motor complete with all sensors and computer and accessories (usually can be found for $1500-$1800 shipped. Look for a '95 model...they have the best distributor and more user friendly computer, but all year LT1's are fine. (I would try and stay away from getting an OBD-II computer though).

If you have any questions on what to do with wiring (the trickiest part of the swap), modding the motor for very good power, or anything else in general...post here or e-mail/IM me.

 

BTW, you don't have to lift the motor out of the car to change the cam you currently have, and the MINIram will not choke out at 4500. 6500 maybe. If your 350 is good, just do heads/cam/intake and your running. It probably will be easier. Isn't an LT1 intake modded to fit a SBC around $400? Well anyways, I've helped with the motor and the intake swaps on cars, so I'm pretty experienced if you have any questions.

 

is there any literature available that documents step by step what to do for an install? this would be very helpful, I will keep in touch with you if I have any more questions to ask you

 

There is no step by step. You just kinda have to merge your knowledge of motor swaps in general and study wiring diagrams of your car and the LT1's computer and cut and splice to make it all work.

 

hey. mark. guess what? i just looked at your site and read your car's story and updates. guess what else? you're officially my new best friend bc i need to do that swap next summer too :sillylol:

please don't let ur site die it'll be a huge help when i change over in june. great job, you definitely have a vehicle to be proud of

 

Thanks....The way I did the swap IMHO is an easy way to go, but it's a little more expensive for sure. I used DFI where you can use an LT1 PCM easily with a good wiring harness.

I'll be updating my site once everything is done to my satisfaction along with personal opinions on how to make the swap work best and easiest, some helpful hose routing schematics, and a lot better quality pictures. According to my site my car isn't done, but I've been driving it around for a little bit now, I changed to a much more agressive cam, and is in right now for dyno tuning...I'm hoping for 355+ RWHP.

 

Heres a nice guide... http://www.lt1powered85z.cz28.com/custom.html

 

Mark, where did you get your heater core cover. I deleted my AC on my RS, but still
want to use the blower motor for the heater
in the winter. Did you make that cover or buy it?

 

It's a factory cover actually. It came on a lot of Base model camaro's that had no AC. They're rare to come by but sometimes you can find one in a junkyard. They're also discontinued from GM so you may have to make one if you really want it. I've seen 'em on Ebay for $150 or more sometimes, but check your local boneyards for a diamond in the rough.

 

I would say get a hold of John Millican and talk to him about a modified LT1 intake for $400. That and a good set of heads will really add power to your motor. Add in a new cam and your really talking. This would all cost about the same or less then an LT1 engine, and you would have fewer headaches and such as all your existing computer and wiring stays as is. You might just need a new chip. But you can buy all the equipment to burn your own for about $200. And the custom tuning will also help. Glenn from the prom board managed to decrease his 20-70MPH time by about 0.5 seconds (if i remember right) just by tuning a chip for his car (a stock L98).