It's not like anyone ever asks for help choosing a cam here :eek: buuuuuttt

It's cam change time....I'm tired of the crappy idle/no vacuum thing

here's my current combo

454 0.030 over
4.25 stroke (489cid)
small SRP domed pistons....compression calculated at 10.32:1
GM performance oval port aluminum 2.25in/1.88ex (same as used on ZZ502)
edelbrock rpm airgap
comp cams XR288HR hydraulic roller cam (@.050 236in/242ex ... .521in/.540ex 110° lobe sep)
comp cams pro magnum hydraulic lifters #887-16
comp pro mag rockers

current carb is a race demon removable sleeve configured to a 820cfm annular booster BUT I plan on going EFI in the next year or so....until then I can change the carb around to whatever I need

exhaust is 2" primary 3 1/2" collector headers to a 3" x-pipe, mufflers and full 3" tails

trans currently is a TH-700-4R with a 2500 stall convertor (a little small for current cam I've discovered lol)
I'm also planning on installing the T-56 I have this winter so cam choice need not reflect the convertor I have atm

rear is 3:42

looking to retain the hydraulic roller so all I have to change is the cam itself......car is mostly a street car....nearest track is 110 miles away and I have to drive it there so it's a "Street Machine" type car...not looking for drag only type stuff, I'm most unhappy with the amount of vacuum the comp makes. max is about 10" I've installed a can and it helps alot for the brakes but it's not enough for the HVAC system to work....oh yeah the car has A/C, power steering and all that good junk too smile.gif

I like the current power level its at but think I could come close with a little less radical cam

any info I've left out?

hit me with your best shots......please ;)

Sure, try something from 274 to say 282 b/c for a BB motor b/c these are more street cams whereas in a SB 268 to 274 are about the limit for STREET CAMS!!!

All the cam companies say anything bigger then can be ran with a stock converter is more into the "RACE" category vs the daily driver thing.

AND this is generally around a 270 cam for the SB's and around a 280 cam for the BB's so please take your pick...

BUT please realize that everybody's idea of a streetable cam is his own opinion of what he wants to put up with!!!

pdq67

well thanks for the reply.......maybe I should just drive it up there and get your opinion lol....what weekend does Jeff City have its cruise? smile.gif

I'll probably just live with it for now and after I 6-speed it and get the EFI in hand I'll worry about changing cam to suit the EFI

That's a thought. Do it when you swp to EFI since it's not likely the vacuum on theXR roller will be EFI-friendly. You'll probably like to go to 112 lsa, maybe, depends on which EFI you use. That's the right time to swap the bumpstick imho.

Hey man,

I'm a little concerned that your cam might not be all your problem.

I've run 240 degree cams in small blocks to the tune of 100-150 less cubic inches in and pull more than 10 inches of vaccuum on the same LSA.

Plus the XR series supposedly has much faster ramps which should translate to lower duration from seat to seat which translates to higher cylender pressure and even more vaccuum.

I'm wondering if your timing or carb adjustment is way off?

That motor should not only run like crazy, and even on the 110, I would think it should pull 15 inches or so. especially with 490 cubic inches.

Aaron has a point. USe UDHarold's quick and dirty method of checking cam timing to make sure the current cam is phased +4 or so. As a rough guess, the intake valve should be .030-.040" closer to the head than the exhaust on #6 TDC.

I had the same issue with my UD cam, in a motor I paid for pro assembly on. Whoops. Cam was in -6, not plus 6. That'll do it. Gained 2-3" on that change.

I degreed the cam myself.......it's been a couple years but as far as I can remember it was installed +4 degrees.....I'll have to find Harolds way to check and make sure I suppose lol

and don't get me wrong the car runs really well...I just don't like the no vacuum and the clatter of the "extreme" cam is begining to aggrivate me a little too smile.gif

it's run a best of 12.56 @ 110mph with the old holley 3310 and regular radials on it, in a car thats set up like a "G-Machine" not a drag car......I drove it the 100 miles to get there and it got 15mpg going 80 on the highway

I just think it could be better while staying close to the same level.....like I said I'll talk to Harold (more than likely, I like talking to people that know what they're talking about lol) about a replacement cam when I have the EFI purchased and ready for install