[doctorofpain]

Couple of questions for those that know-- did a search on a 454 swap and got some info but was fairly old so here goes. I have a 78 with a 305 with A/C and a turbo 350 tranny. I have come across a good 454 for the right price so I "may" forgo the 350 engine swap and do the big block. Any major issues with size, extra weight and transmission bolt up? Thanks for any info. No real reason to go with the big block other than the cool factor of having one.
Doc

 

[60ElCam]

Many members here have done the swap - 454 Chevy, 455 Buick and even a 500 Caddy if I am not mistaken. Major issues will be weight difference - more HD springs in the front. Frame bracing - the frame was never intended to handle that kind of torque and twists the body to the point that the windows start to leak. Rear axle strength - the 7.5" ring gear 10-bolt does not hold up to the torque. All these things can be overcome, but a simple swap it is not. The engine will fit under the hood, but is really tight to the A/C box. I do believe they make BB headers for this application - not sure of price. A THM 350 or THM 400 will bolt up to a BB as the small and big blocks have the same bolt pattern. Tranny Mike could tell you of the differences / needed upgrades.

That's a quick synopsis. Big shoe-horn and upgrades and you will melt the tires at will . . .

 

[doctorofpain]

good info - thanks

 

[1983SS454]

Its actually a very straight forward simple swap, the biggest challange is making the drivetrain hold up to the power. But with an automatic trans the 7.5 will hold up for some time as long as sticky tires are not used. I personally wouldn't use headers again, I would just run manifolds. Headers are very expensive for this swap. The engine will fit under the hood using the right manifold/carb combination, easy solved with the addition of a cowl hood.