I just bought a 1986 LS monte carlo. The guy before me has done some work, including an engine swap from the stock 262 motor to a carburated 91 chevy 350 from a truck (a 1500). Also it has a Edelbrock hi rise carb and performer rpm intake, and Hooker headers, so its making quite some more power then the stock motor. I have driven it and it seems to work fine, but should I be concerned about the extra torque and power and do I need to rebuild or switch out the rear end and driveshaft? Im not sure how much more its putting out but I'm wondering if I switch it for even one from a SS model if it would be able to handle it all.


Thanks for the input

 

idk what kind of power you making but i doubt its enough to break the rear. the 7.5s should be the same from the ss car to your car with exception of possibly a posi and possibly better gearing depending on whats in yours. they should both be 26 spline and have the 7.5 ring gear. you dont have to get the ss rear you could always buy a 28 spline posi carrier and 28 spline axles for yours and what ever gearing you want. but at that point your at half the price of a cheap dana 60. its all up to you but if your not planning on making more power you should be fine.

 

Nah, you don't need to worry about the driveshaft unless you plan to be making some REALLY hard launches off the line. That, and the flywheel ratings of that engine is nothing to worry about. Unless there's more to it than those bolt-ons you listed. Otherwise I'd make a guess of around 250HP and 350TQ at the crank. And the only way I think you'd break the rear with that is if you were to drop the clutch, but it's a 4th gen Monte, so unless you've made a trans swap, there's no worry of that happening.

Then again, if you take it to the track with some stickies, and all the stars line up, it's still possible something will break when those tires grab. I don't think it's likely, just possible. But everything is possible. I think the best route for upgrading the rear end, if you want to do it on the cheap and easy, is to get a low mileage, complete rear axle from hub to hub from a salvage yard. The best possible thing you could get that came in a G-body would be the rear out from under a GN, though good luck finding one of those sitting in a salvage yard.

 

Yea its just really simple bolt on's nothing crazy. And I'm not planning on any more power in the near future, my next two phases are putting the car on a major diet, hoping to cut off about 300lbs or so, and then all new (and probably semi race) suspension to make it quicker and less strain on the rear end. And yes, I have been on the lookout for a GN engine or rear end for about 6 months now and no yard is gonna have it, or theyll know exactly what they got and itd be pricey. I didnt think it was gonna be a major issue but im more used to tuners not domestics and I know its a whole new world so I wanted some outside advise to ease my thoughts. Thanks again!

 

Unless you plan on doing some hard launches at the drag strip and building that thing up, I don't think you have anything to worry about from the rear end, much less the driveshaft. I think the advice posted here by others before me is adequate for your situation. Just keep driving and enjoying your Monte Carlo!! Thanks for joining and feel free to keep posting!