The RAM AIR IV CAM IS NOT A GOOD ALL AROUND CAM, IT NEEDS COMPRESSION LIKE 10.75 TO 1 OR MORE TO WORK GREAT, REALLY WORKS GREAT WITH 11.5 TO 1 PEOPLE REV IT TO MAKE IT WORK WITH 10.5 TO1, THIS IS IN A 400, IN A 455 .030 OVER HAVE TURN IT ONLY5200 RPM WITH 11.2 AND 4000 STALL CONVERTER AND HAD IT WORK GREAT. 068 ARE A HO CAM 744 IS THE RAM AIR ALONG WITH THE RAM AIR IV 044. THE RAMAIR IV HAS SLOW RAMP SPEED ALSO. IF YOUR RUNNING LOW COMPRESSION I WOULDN'T USE EITHER THE RAM AIR IV OR RAMAIR III CAM. THE 068 WILL WORK BUT= A BETTER CAM WOULD BE A LUNATI part #10510702 or #10510703 BOTH WORKS WITH LOW COMPRESSION AND BOTH IS SPLIT DURATION. REMEMBER VALVE SPRINGS PLAY A VERY IMPORTANT ROLE TO MAKE A CAM WORK.
Call Jim at Racer Brown cams in Baltimore. He has a .470 lift cam that has been used in more than one 400 and works very good. Racer Brown 410-866-7660 2pm-8pm eastern.
Be careful with the lift, your heads are made for .407" lift. You should have more spring if you plan to go bigger lift. The Ram Air IV cam came in 400's, no a/c, had to be a 4 speed, and 3.90 or 4.11 gears. Your car should be lighter then the GTO so you could get away with it. It won't idle very will, but it will sound good. I ran one for years with great success. For a $100, you can get the 2801 cam from summit with lifters. It will pull hard up to 5500, sounds good, and idles pretty good, pretty much a copy of the 068 HO cam. You would not be disappointed in it. A solid lift cam will not perform any better then a properly spec'ed hydraulic cam, same with a roller cam. All the engine knows is the valves are opening and closing, and if all three types are equal, they all will perform the same way. With that said, the hydraulic will be easier on the lobes and lifters. Dad and I both raced Pontiac's for years with Rhoads lifters. With a RA IV cam and Rhoads lifters, you could have decent idle with great top end power. Dad's wagon ran 11.40's @ 116 mph with a similar setup using Rhoads lifters, and his car weighs in at 4200 lb with a 3.31 gear ratio. Joe
I'd listen to Joe H [I know his dad, Jim] because of the research they've done on Pontiacs on the street and especially on the strip. Joe's dad has a killer book on what works and what doesn't regarding Pontiac V/8s. That said, I've used the single pattern Lunati 230/230 @ 110 lobe centerline cam..it's got .490 lift which required me to trim about 0.50" off the bottoms of my valve retainers....springs are not close to binding but I didn't degree in my cam on this build. It was cold in the garage, my dog ate my degree wheel etc blah blah.. Seems to run great so far.
Joe, Not trying to split hairs here, but the '69 -'70 RAIV 400 engines did come backed by a TH400 auto trans as well as a 4-speed. A 3.90 rear gear was mandatory with the RAIV with 4.33 gears optional, no 4.11 gear was offered. Say hello to your dad Jim for me. Bart
Melling Tool Company was the OEM camshaft supplier for Pontiac. However, Pontiac did make available for certain NASCAR and drag strip drivers a series of ISKY solid-lifter cams coded E-1 through E-4. They had approximately 300 deg duration both intake and exhaust and about .420" lift with 1.5:1 rockers on 110 deg lobe centerlines. These ISKY cams were only available over the counter, these were not production cams.