[CNUDIGIT]

Hey guys i recently purchased a 1972 grand prix model J, looking to restore it it came with rebuilt original engine 400, new mild cam, racing carb. I have a small leak around the main seal where engine and trans connect i put in some stop leak, waiting to see what that do, what are some tips you guys have used, also should i rebuild that trans or upgrade to turbo 400 4 spd with overdrive. one last thing should i use a lead additive to the fuel since gas back then did have lead in it. Thanks

[blue goats]

Welcome
I don't think stop leak will fix a rear main seal leak. You'll have to replace it with a neoprene one. The rope seals they sell today only work for awhile in my experience. Once the car sits for a while they leak. Regarding the trans , is it bad ? Changing transmissions is a personal choice for me. Some like overdrives some like just stock and some prefer powerglides for racing. As for the lead I really don't know. Has the car always ran with some sort of leaded gas previously? I've been told once you run unleaded thru the car for a couple of tankfulls the damage is already done, whatever damage that might occur has already occurred.
Hope this helps and welcome again
George

[67 Lamnas]

Originally Posted by CNUDIGIT

Hey guys i recently purchased a 1972 grand prix model J, looking to restore it it came with rebuilt original engine 400, new mild cam, racing carb. I have a small leak around the main seal where engine and trans connect i put in some stop leak, waiting to see what that do, what are some tips you guys have used, also should i rebuild that trans or upgrade to turbo 400 4 spd with overdrive. one last thing should i use a lead additive to the fuel since gas back then did have lead in it. Thanks

Welcome to the forum.

If the engine still has the original heads, (code 7K3), the valve seats are already induction hardened...believe the first year was '72 for this.

Your stop leak won't help. If it's the rear main seal, you can go with a neoprene seal like the BOP, or if it were me, I'd go with a Graphtite rope seal.....Pontiac Dude sells them. It could also be the rear pan seal that's leaking.

If your trans isn't broken or leaking, then run it as is.

http://bopengineering.com/

http://store02.prostores.com/servlet...ude/StoreFront

[CNUDIGIT]

Ok thanks for the great info fellas ill do some research on this. ill also take it to a transmission shop to see what will be best route to go. the guy i purchased the car from used 93 in that car, do someone know how to take out the radio and see if it can be rewired or something, i love the sound of the duals but would like couple song to cruise to

[torqjunki]

CD-2 will work with a rope seal. Had one dripping about every 10 sec when idling. I would still get that damp area around the rear seal area after many street mile, but no drips. Not advocating doing this instead of fixing it, but if your trying to put it off for some reason, worth a try. O'rielly has it as well as Napa.

[CNUDIGIT]

Thanks, I have a questions would it be better to get a new trans or just rebuild the current one, looking to keep most of the value high for the car as much as i can. any suggestion.

[getmygoat]

original cars are worth more than modified cars generally ... although if the car is just a regular GP (not SJ or other rare model) - the value isn't hurt too much by swapping the trans, especially if you keep the original one and sell it with the car when you do sell the car.

It also depends on the type of driving you do a lot of - if you are mainly on back roads, under 50 mph, then I would keep the original trans - if you do a lot of highway driving - then the overdrive would be nice for ride comfort(noise) and mileage - along with wear and tear on engine.