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Hello all, I am wondering about a cam recommendation for my 76 C3. I will be using a chevy 350 bored 30 over, weiand intake, AFR aluminum 200cc heads with 64cc ignition chambers, flat top pistons to achieve 10 compression, long tube hooker headers, and a Holley 750cfm carb. I am bouncing between a comp cam XE268 or XE274. My rear gears are 3.08 with my TH350 automatic transmission. I would like to know people's thoughts on these cams. I have had the XE268 cam recommended by a couple people. I am looking to feel like I am driving a sports car and not the L48 stock motor I had that was a slug before. Can anyone give me insight on these combinations or recommendations on alternative cams?
Is this the numbers matching engine you’re working with? And is that something you care about?
If not you would be light years ahead finding a later block already set up for a hydraulic roller cam and using one of them instead.
Otherwise those heads have too long of runners for the powerband you want with the 268 cam, and if you go with the 274 you’ll really have to rev it to get into the powerband, something that would take forever with your 3.08 rear end.
If this is the stock block and you want to go with a flat tappet I would go with the 268. If you want AFRs I would go with smaller runners (180), and if you want it to drive “like a sports car” I would increase the rear end ratio.
Since you’re doing machine work it doesn’t exactly apply, but here’s a thread about L48s.
Last edited by Piersonpie; Nov 21, 2025 at 10:46 AM.
I've always heard good stuff about the OE '962' cam (GM# 3896962) used on L46 and L82 engines. I don't know that it's specifically available these days but perhaps there are comparable models...? Specs are out there so could also compare to the models you are already considering. Good luck
sports car feel ? first, swap that TH350 automatic for a manual trans. That, alone, will up the sports car experience in spades.
Or, realign some expectations.
I believe 200cc volume intake ports are probably too large for your implied/stated goals. Too big ports, too little displacement, too big cam and an auto trans will likely thrust you into an extended gearing-jetting-tuning battle; trying to sort out a car that'll likely run poorly and drive poorly as well.
Perhaps, acquire a rebuildable core, '96-2002 rpo L31 Vortec Gen 1 sbc 350; then rebuild that 'truck motor' ?
L31 comes OE with roller cam-lifters & decent heads; and L31 bolts up directly to your chassis and bellhousing-trans.
L31's a very popular retrofit; but note: GM Vortec heads Require an 8-bolt intake manifold with Vortec bolt pattern.
FWIW: GM offers Several brand-new performance crates based on L31 architecture; while continuing to supply brand-new replacement L31 long blocks.
I'll throw in my 2 cents as well.
Those heads are all wrong for a 350.
I agree, drop down to 175 or 180 runners on a 350.
The XE268 cam works well with a manual and 370 rear gears. I know, I run it.
3:08 gears? 350 automatic?
This set-up just isn't going to work.
I had the Xe268 and it worked ok, but I have a manual transmission with 3.07 diff. I switched over to a XR276 roller cam with the 2.02 valves and the 185cc intake runners. Runs good, but 3.55 rear end would probably make it better. On the highway It runs pretty well. RPMs were at about 2900 to 3100 at 75 mphs. I ran it 830 miles round trip last week and had no issues. I have the Flowmaster 40s so it was a little loud at 75 mph, but at 65 you could actually have a conversation in the car.
If it is an automatic you might have to change your Torque Converter with that cam you want.
If you realll. Good luch y want to get the most out of all your doing you are going to neet to change the rear end gear . 3.08 are to tall and no cam I know of will like them. Consider some 3.73 maybe but what ever you do match the cam to the rear end gears and of course beware of maybe needing a stall converter. If you really want the sports car feel as others have said you need a manual 5 speed overdrive then your going to be rocking it
Either cam is too much for 308 gears.
You really need either a smaller cam or more gear.
With one of those cams you will be 3 car lengths down the road, and over 30mph, before the cam starts to pull hard, with that gear.
That gear needs a cam that pulls from 1200 to 1400 rpm.
Actually my first interation on my automatic 350 with a 308 rear, was a cam similar to the 268 cam and 9.9:1 CR. And 200cc heads. Not what I wanted, but how the heads cc'd despite being advertised as 180 heads. They were cast, and not very accurately.
Anyhow my point is it is possible but...what you will need is a higher stall converter to make it work decently. At least that is the cheapest route to go. Better is to get the CR up a bit higher if you want to keep that 308 and get a 3000 stall converter. Best is what these guys are reccomending. Depends on your budget really.
If you have not purchased the heads get 180 or 175 heads, you will not like the 200cc heads. Best is the AFR 180 eliminator. It's what I run. Yes they are expensive, but very good quality and literally plug and play.
All XE flat tappet cams have Very Fast, Very Aggressive ramps; as such, they're historically prone to flat tappet failure. As are most cams with similar lobe profiles.
I like the Comp 268H cam, but not the faster ramp XE variation.
It could work very well, with your 308 gears, IF you put a 2500-2800 convertor in there. It will work but feel a little sluggish with a stock convertor. It will be a lot stronger than your current L48, and it will feel more sporty, because it revs harder.
Stock convertors are roughly 1700 stall.
This one would help quite a lot with that cam. So would many others.
If you have never driven a high stall converter, they only go that high at full throttle, with brakes locked. Usually they are much less.
Cam question?
