This car is my first ever build and i don't know all the ins and outs of my engine. I bought the engine already built and i know it has flat top pistons and the crank has been turned but im not all sure what i have i side the engine exactly. I just got my trans rebuilt at a trans shop about a year ago and the trans shop rated it to 550 - 6ish. Again im not 110% sure what i have and im not in the position to replace the 7.5 as i just put that posi unit in there and i am on a small budget. Im looking to learn and try new things if you have any suggestions on anything i can do without changing too much. Thank you
If at all possible try to get a spec sheet from whoever you got the engine from on what went into the build. Same on the transmission.
To be honest, the old adage applies now as much as ever: "You can go fast, cheap, and reliable. Pick any two."
This isn't being a smart alec, but you shouldn't mod anything you can't afford to break. A lot depends on your goals and all those unknowns about what you're starting with.
Let's assume the trans might hold 550hp, pending paperwork to back that up. Safety factor says push you build to 500 if you want it to last a while.
At 500hp that 7 5 rear will die. Not a question of if, just it's when. It doesn't sound like you upgraded the axles, installed c-clip eliminators, support cover, etc... or maybe you did. But a 7.5 with just 4.10s added won't handle much power driven aggressively for long. Axles will break as most likely failure point.
The cheapest and possibly longest lasting power adder would be the nitrous shot
565bbchevy recommended. Benefits beyond cost are it only stresses the trans and rear on demand, and the rest of the time it's a lower level of force being applied there.
Really you need to know what you've got to start with, which means bugging the shops that built the engine and trans
