88suprmclassic said:
Don't want to make any of you purists sick,but, I am considering putting a SBC in place of the 307 Olds with emphysema. I know some of you feel it to be sacreligeous.Cannot find any information on what exactly is involved. Wish the car was canadian built with the 305 chev. None of the 88's probably came from there. Would like to talk with someone who has done it and what specific roadblocks I will come across during the process. Aside from the obvious motor mount, crossmember, drive shaft length, and power steering issues I know exist. I need specifics. Or enlighten me on whether or not the cost/h.p. benefit leaves me better off going with a 350/403 Olds. I wan't it to MOVE. Always loved the G bodies
The 88 Cutlass came my way after inquiring about it two years ago and I got it two years later for a whopping $1000. It only had 400 more miles on it then when I tried to originally buy it in 03'. Could not pass it up. But the Olds motor issue bothers me. Would of rather had the Grand Prix or Monte (Non SS). But I will be happy with the Olds when I am done!
Firstly, Hi to you and other G-bodyers. Cool to have a decent forum for us out there now.
I did this swap last spring and it's the best thing that ever happened to the car. DO NOT listen to the people who tell you that the expense of making your car Chevy-ready will outweigh the cost of acquiring and building an Olds motor, it's nonsense.
Here is what you will need:
There are bolt holes in your factory crossmember to accommodate the Chevy mounts. However, you will either need to dissassemble your front suspension to bolt them in, or do what I did.
I simply put the bolts in (without tightening a nut on the under side) to assure they were lined up, and welded the mounts on. I'm by no means a good welder, and my mounts held up to several swings of a sledgehammer, so as long as you have someone who can weld decently do it, they'll be stout enough to take whatever you throw at them. But do test them to be sure.
Crossmember is ONLY an issue if have a TH-2004R and plan on going to a TH-350 or 400. If you have a TH-200C, you are in luck, and your stock crossmember and driveshaft will work with a short-tail TH-350. I went from a TH-200C to a TH-700R4 and it was a simple and cheap process. The 700 is about 2.5 inches longer than the 350/200/400, so all you have to do is drill a new hole in the mount tab about 2 inches back for the new mount location, and get the driveshaft cut about 2 inches or so. I didn't have to fab a new mount or anything, I used the stocker. Not a big deal, people blow it way out of proportion.
I'll add that if you do have the 2004R, I would keep it. The best of the 4 speed GM overdrives in terms of ratios. My 700 is nice, and helps to offset the pathetic rear axle gears in this thing, but the drop in RPMs during the 1-2 shift is pretty bad. In addition, the 2004R can be built pretty stoutly, as many Grand Nationals have proven.
My donor motor was from a freakin 85 Suburban and the power steering still was interchangeable and problem free. The hoses were a little to long, but I managed fine without any problems, and if nothing else I could have bought shorter ones. I expect your donor motor's PS system will bolt up similarly, as mine was from a totally different platform. If not, at least you know an 85 Suburban's will.
Other than those issues, the only thing to address is wiring, and it's really not too difficult. Depending on your donor motor, your wiring may or may not be on the same side. If you don't want to buy the extra wire to run it across, you can get an alternator bracket from a car like a 3rd gen F-body which has the alternator on the driver's side (like an Olds). But your starter will be on the opposite side regardless.
The fuel pump and lines will be on the same side.
I really only had to weld the mounts and spend 30 minutes with a grinder and a drill on the crossmember to cut the tab back a little and drill a new hole. I probably spent $50 total on it, for most of the same stuff you buy for any motor swap (new mounts, etc.).
You should know that you will need the mounts off of the chevy motor, and most likely your stock Olds exhaust system WILL NOT work with your Chevy motor. Excellent time to spend $150 on a Summit-brand headers-back G-body exhaust system and install it.
As for the overall advantages of the swap, you probably know most of them. Chevy parts are cheaper and the aftermarket for the Gen. I smallblock Chevy is the best out there. The Olds die-hards will try to argue you on the bore/stroke and higher nickel content being better on the Olds smallblocks, but on a street/strip car, the advantages of the Olds block are negligable.
Bottom line is the Chevy smallblock has easily the higher hp to $$$ ratio, and has a firmly established reliability record.
The Chevy motor is also noticeably lighter than the Olds, and you can plan on weight reduction from the swap. That high nickel content has it's drawbacks.
I have nothing against going with an Olds motor (especially a 455 8) ), but do not be fooled. The Olds to Chevy swap is not difficult and CERTAINLY not expensive.
Good luck, whichever way you go with the swap. Be it 350 SBC or 350 SBO, it will be a lot more fun than your 307.
