I need to replace my camshaft and I would like some suggestions. The car is all stock, so I am looking for a stock camshaft or one that is better, but Not racing—oriented.
Your car as you noted would have come with the 254 cam, so the 066 cam would be an upgrade. I'm thinking the Melling SPC-5 is the 066 replacement.
The 068 replacement that Ames is selling is the Melling SPC-07. This was the performance cam for some of the 400 applications and would likely be the largest of the stock cams to consider to maintain a near stock idle, in my opinion.
You might also consider the Summitt 2800 which should fall in betweenthe 066 and 068.
Have you upgraded to a 4 barrel carb and intake? I would add that to the list of things to do.
A valve job and new springs should also be considered along with the cam and lifters.
All the above should provide you with a nice runing 350.
1968 400 Coupe, verdoro green, black vinyl top 1968 400 Convertible, verdoro green, black top 1971 Trans Am, cameo white, auto 1970 Buick Skylark Custom Convertible 350-4(driver)
I'm not a camshaft expert, but there are a few things you should consider before changing the camshaft. The camshaft for the 4 barrel 350 was in an engine with a compression ratio of 10.5:1, yours stock is 9.2:1. I think the four barrel heads had 68 cc chambers and the two barrel head had 72 cc chambers. In order to see/feel any difference you will have to rev the engine faster, the four barrel with the 066 camshaft has a power/torque curve at 3200-5100 RPM and yours is 2800 to 4600 rpm. You will most likely have to idle faster than you do now to smooth it out, You'll also have to think about breathing, the 066 operates in a car with a larger CFM carburetor than you have, I don't know what differences there were in the exhaust but I imagine the four barrel had more flow. Then there is the rear axle ratio. usually the larger one goes with a camshaft the steeper the rear gear is.
I'm not saying it's a bad idea to switch but one has to think of all the other variables before changing one component.
As Wovenweb says, a valve job wouldn't hurt. You'll have to pull the heads for that. and this would be the right time to change out the timing chain and gears.. Check the condition of the push rods and rockers while they are out, they may need replacement. If you re use the rockers and push rods make sure they go back in the same position they came out.
If I had the choice, I would prefer to keep my 9777254 cam or buy another aftermarket with the exact same specs as my camshaft. But the mechanic who is rebuilding my engine says I need to change it. He has been working on old cars all his life and he worked on my previous car. I do not think he would have asked me to change it if was not needed.
This is the reason I am trying to replace it with an aftermarket cam that will be similar to the OEM camshaft.
But, that cam does have more lift than the small Pontiac cams. Exhaust lift is .444. Don't know if this cam will work with tired stock springs, or not.
The 066 cam was used in the low compression '74 350 GTO engines.
I would go easy if you're building a cruiser, I have a 400 with the Crane Blueprint RA I cam, anything hairier and you won't like it, your motor won't idle below 850-1200 depending and it's going to stumble until you hit 2000 and then fly to 6000, your mileage will suck, mine like to cruise at 2000 with my gearing. The RA I & III are good cruisers, the RA II & IV are the same cam the IV has 1.65 rockers, they're racing motors and they need special springs etc to work. If you're going aftermarket you're looking for something that's idle-5000 or 1500 - 5000.
Pontiac 9785744 301 313 224 236 .410 .410 119 RA III
Pontiac 9794041 308 320 231 240 .470 .470 114 RA II & IV
looking at those now you'd probably be happy staying away from anything like the II, III or IV, the RA I cam was already in use as anything HO in 67 so that's what they used, it's only slightly radical, fairly smooth idle, anything like the O66 or 67 will be good too
Actually, I think the Comp 51-220-4 best for your setup and desires. Adv Durations: 250/260 0.050" Durations: 206/212 Lifts: .432/.444 LSA: 110
It will exceed the off-idle torque of the stock camshaft, while still breathing much better on the higher rpm than even the Summit, 066 or other Comp you listed. Should have really nice throttle response too. Possibly a slight lope at idle if anything. Definitely upgrade the springs, and timing chain while you're in there.
"... I think the Comp 51-220-4 best for your setup and desires..."
That is an XE series steep ramp cam. These type cams were intended to increase cylinder pressure in low compression engines. But, if you choose to go with one of these type cams, I'd go with a Lunati Voodoo, instead of a CC XE series cam. Many Pontiac guys say that because of the steep closing ramp, which slaps the valve shut, the XE cams produce a ticking sound which some can't live with. I'm sure that some find it perfectly acceptable.
The closing ramps on the Voodoo cams were designed to close the valves more gently. The small Voodoo cams also have a 112° LSA, which is said to produce more vac & a smoother idle than the 110° LSA of the XE cams. Lots of guys love the Voodoo cams for Pontiacs. Well known Pontiac engine builder, Paul Carter, has used & recommended Voodoo cams for years.
" The closing ramps on the Voodoo cams were designed to close the valves more gently. The small Voodoo cams also have a 112° LSA, which is said to produce more vac & a smoother idle than the 110° LSA of the XE cams. Lots of guys love the Voodoo cams for Pontiacs. Well known Pontiac engine builder, Paul Carter, has used & recommended Voodoo cams for years.
I had considered mentioning that one, but had recently read somewhere about quality issues with Voodoo cams, so wasn't sure if they were still good. Spec-wise would be a great camshaft with a little smoother idle. Lot of the idle comes from relative intake duration vs. engine displacement along with valve overlap. The comp what might seem like a "tight" LSA @ 110. But because the duration is relatively short, the actual overlap would be small, and it's a very mild cam for a 350 engine.
