Ok i just bought a 75' 455.. i really dont know to much about motors so i need some help! im going to get it cleaned and rebuilt, im not trying to build a track motor but just a stronger than stock 455.. My goal is to pull 400hp out of the motor dont need anymore than that, so my question is what is the easiest way to do this? im planning on getting the heads ported but other than that what else should i do? .... Cam? and if so which one?... Better Valve Train? Headers? Upgrade Carb and Intake? If so which carb and intake should i go with? I may want to run the motor once or twice at the track just to see what'll do but no more than that, Im also aware of the poor oil return system of the 455 if im not really planning on running this motor hard (well not too hard) should i worry about an oil restriction system? im lost and just need some direction... GOAL: 400HP AND A GOOD "EVERY NOW AND THEN DRIVER" thanks guys!

Also will my motor mounts and exhaust manifold off of my stock 307 work for this 455? and i want to go with posi- traction so whats the best way to do that, what gears or rear end should i go with? (remember not a drag car!)

 

I would buy an aftermarket cam before spending money on porting. IMHO, intake, headers, and an upgraded carb should also come before porting work. Don't worry about upgrading the oiling system if you don't plan on racing very often. I've heard this is a problem for people who like to turn alot of RPMs constantly.

 

Ditto on the porting. No need for it.
Do make sure that you have 2.072 intake valves, and a fresh valve job.
The fancy valvetrain is for adjustable valvetrains, and/or larger cams that require much more spring pressure. Just make sure that you have 125# ON THE SEAT, AND NO MORE THAN 350# open pressure. 275 open is fine. You should only need to rev this to 4600. Performer manifold, and a q-jet. 1 inch plastic spacer. 38 deg timing all in @3000.
Do not worry about restrictors, just make sure your builder opens up the main feed holes, and that they are lined up correctly. Also you need at least .0035" #1-4 mains, .0045 on #5 main. Chevy guys never grind Oldsmobile crankshafts where they need to be. Stock toro oil pump, and pan.

Do NOT use the 307 manifolds, just too damned restrictive. Get some headers, or some W/Z manifolds.

You will need more compression for 400 hp. Shoot for 9.5:1. That will mean some pistons. If using L2323 speed pro's, make SURE they are pin fitted (they come too tight), and that you have at LEAST .004 piston to wall clearance. The mfg recommendations are too tight, and that is a proven fact.
307 mount will work fine, drill a 7/16 inch hole through the center of the drivers mount, and put a 7/16 bolt and nut through it. Clearance everywhere the bolt wants to hit.
3.23 gear with the posi would be the hot ticket. 3.08 would be my 2nd choice. NO 2 series gears.
A 455 like this will scatter that 7.5 rear axle in no time flat. Another fact.
Jim

 

Hey,I also have a 83'OLDS destined for a 455.Go to the WIKI forum on here,lots of interesting reading there about these engines.Also ''Robert powers motersports''has a complete swap,with all youll need to put a 455 in a g body cutlass.A must read!Good luck,later,BO

 

thanks alot for the Info Jim!