Just bought a Holley 7455 for like $25 it's a kinda qjet Holley. It's a small 4 barrel Rated @ 450 cfm. You guys know anything about these? Thought it might do nice on a 250 with headers and a low end torque type cam your thoughts? Looks like secondary are mechanical guess I will see when it arrives.

The 390 cfm Holley would probably be a closer match on a 250, but on the other hand,a new Holley 390 cfm carb is going to cost a LOT more than the $25 bucks you paid for the 7455. So if you wind up a wee bit over carbureted, no big deal. 450 cfm is still pretty close to what a 250 would need, depending on what sort of modification has been done to the 250.

Yes I just happen to run 3 of them on my 3x4 tunnel ram intake.

You can always de-jet the carb if it does seem to be to much. And Yes most are all Mech. sec. Which as you get to be at half throttle they will start to pull in.

I read up on it a little and regular holley jets won't fit, but I read weber jets will. Guess I could also maybe tap it out I don't know seems I heard of guys doing that but will probably go with weber jets if needed. Holley also still make kits for them.