I'm in a bit of a delima, i recently bought a 72 gs hardtop car that originally came with a 350, (no engine or tranny came with car). So I've lined up a 455 which i'm suppose to pickup this weekend and my knowledgable buick buddy drops the bomb and says the GS 350 frame part # is different from the GS 455 frame part #. :spank: He's suggesting I find out whats different on the frames, if anything serious, I figured its prob no big deal and its been done many times but my wife will kill me if she finds out I bought anouther engine and this ones not going to fit??? This should me no big deal right or wrong? I really want to install the 455...any advice soon would be appreciated o No: . thanks Gord
Group 7.003 Frame "71-72 3437 (455 eng.) = # 1237139" But a 3437 is a GS ( 350 and 455) in 71. So I see what he sees in the parts book but I am not sure he is interpreting it correctly. It is ambiguous at best. He may be looking at a a series 3436 but that is a wagon frame. I think the only other A body frames those years were 4 door and converts. So look for the above part number. I suspect it is correct for both 455 and 350 and 250 cid cars in 71-72. Also ask some people on here with a lot of practical experience. JW, George N. And Duane come to mind. Many ohers I bet too.
frame mounts are needed you need to buy a pair of conversion frame mounts. (POSTON sells them http://www.postonbuick.com/eshop/10Browse.asp or maybe a used set from a member here) The holes should be in the frame already. It is a bit challenging with the control arms in, but, they go. Verify that the frame is not bent first, that is a real pisser after the fact :TU: Also, be sure you have a rear sump oil pan on that big boy :beer
I believe the 71-72 455 frames are a little bit thicker, though I am not 100% positive. As far as putting in a 455, just get the right frame pads/motor mounts and go nuts!
Frame difference Yes they are different. The steel in the front section is thicker. I measured them both. Dimensions are the same as far as I could tell. Maybe a few differnent holes. The 455 fits fine with the 455 frame pads.
As I remember there was a difference for 70 models only...the GS455 was a different part number due to the base material being a thicker gage metal. In 71-2, the GS models were "supposed" to use the same frame as the 70 GS455 models. I have the info on our site for converting from a 350 to a 455. Make sure you have the correct throttle cable brkt for the 455, you need one from a 70-72(pictured on the site) and you will need to buy the new throttle cable from Frank McIntyre.
Thanks again guys, i'm a long way off from mounting this engine, (which i haven't got yet). Thanks for the info on the frame pads, i will need new engine mounts as well, possibly an upgrade from aftermarket sources? When i was dissasembling the car I noticed alot of flex in the frame with no fenders on it. If the frame is thinner and with some rust I'll have to pay close attention to that area. George..i will be checking with you for the conversion parts and prob more advice down the road, thanks again gordon
My 71 has a specific GS 455 only code and part # stamped on it that I found behind the left rear wheel. The 350 has a different # for some reason. Found the name HAYES stamped as well. Must have been frame manufacturer.
mounts A pretty good $$$ deal is the kit from POSTON which has both the motor mounts and frame pads. :TU: If you have a chance, drop the lower control arms out of the way to gain you better hand access to the inside of the frame as you will need to get the nuts off of your old pads and the blind bolts on the new frame pads. This should not be an issue since you should be upgrading at least your springs at this time, before the engine is dropped in. :TU: Man, it has taken hours off the job with the control arms out of the way. HOURS!!!!! :TU:
Thanks again for all the advice guys, Poston is sending me their book, I'm going to totally dissasemble the front end for frame sandblasting and painting. I'd like the car to ride like its on rails at least alittle better so my :moonu: don't tightn up when I see a corner coming...i'm looking for info on possibly lowering the ride height front and rear? tubular front suspension or can the stock setup work ok? I've saved some $ on the engine (i hope) so I'd like to upgrade the suspension and brake setup. I currently have 4 drums, I'm wanting this to be an street driver so I'd like to be able to run with my buddies on the freeway, stop and turn with confidence :laugh: .
I'll do a search or post it in a new thread in parts wanted, anyone think these will work? 2" DROP SPINDLES ON EBAY http://cgi.ebay.com/ebaymotors/ws/e...MEWA:IT&viewitem=&item=260061330477&rd=1&rd=1
I measured 4 cars today: 1. 70 GS Stg1 conv 2. 70 GS 455 coupe 3. 70 Skylark coupe 4. 70 Skylark conv All of the frames measured the same thickness......0.125" sheet metal stamped to form the frame...I measured the front frame horn and the rear frame rail near the gas tank.....same thing on all 4 cars.
This might put your mind at ease. I bought a very nice frame for my car that had been patched, but it was a small patch, and done very well. likely stronger than new. The rest of the frame was beautiful- no pitting, nice and smooth. it was very chincy, two guys could lift it easily, probably 1 if it wasn't so bulky. once I mounted the body back on the frame, It flexes something fierce when jacking from the front be fore I put the fenders on. The frame gets alot of its integrity from the body. most people think its the other way around, but its not. :3gears:
thanks Joe, I had hoped the body tightned the car up, so I guess the body should be fairly solid especially the front end eh? I picked the 455 engine up on the weekend, had the body man over today and he says it doesn't look to bad so here we go time to start spending some money on replacing them rusty body panels.
The "cradle" aka the front crossmember is what is thicker, not the front frame horns. From '70-72, Pontiac A-bodies with factory installed 455, also received their own 455 specific frame. I own 4 such Pontiac A-bodys & have examined hundreds of frames upon processing & before selling them. The purpose for thicker frame cradle was over the years, as the higher torque engines rocked to the passenger side, the frame became fatigued under the passenger side mount. For the '70-72 455 installations, Pontiac went with a larger wider steel frame bracket, longer motor mounts, & thicker frame section all to help alleviate this condition. Buick engineers went a similiar route. When proccessing parts cars, besides evidence of frame cradle fatigue, the typical spot I usually see damage in any pre '73 A-body frame is coming down the sweep behind the lower rh control arm mount. High mile A-body musclecar frames are often cracked in this area. Got Posi? :3gears: Roger
