I got a 73 cutlass supreme coupe, just rebuilt the engine ( 350ci ) and installed the whole edelbrock performer rpm kit ( cam, intake, aluminum heads ) 1 3/4 primary headers, a holley 670 street avenger carb. The heads were decked to get a 10:1 compression ratio, the cam was installed retarded and the intake manifold was port matched to the heads. The timing is set to stock specs. The engine runs good but seems like im towing something, its really sluggish, and also it 'pings' at higher rpms. I know this is a heavy car but there should definatly be more performance. It seems like its running lean due to the sluggishness and the pinging at higher rpms, so i rejetted the carb to #69 primaries and #73 secondaries, but didnt make a difference. Im gonna step up to a holley 750 hp series carb, but wanted to know if anyone has had a problem like this or has any suggestions. Any help would be nice. Thanks.

 

Thanks for the reply, the engine has approximatly 580 miles on it now so it isn't exactly BRAND new but still new. As for the cam timing, what I meant was that the timing chain I installed has 3 keyways. One is to install the cam 'straight up' one is to install it retarded ( for more low end torque ) and one is to install it advanced ( for more high rpm horsepower ) in relation to no. 1 cyl. at TDC. But the IGNITION timing is set at stock specs. which i believe was 20 degrees BTDC at 1500 rpm. I agree it seems like mabey too much timing at higher rpms but when I back off the timing to 10 degrees I still get the pinging, but the performance is like towing a bus. The car seems to respond well at 20 degrees. So I dont think the detonation is from over advanced timing, but from a lean a/f mixture. I read an article on mondellotwister.com about olds 350's that said these engines like 750cfm carburetors. Oh and the carburetor is a holley street avenger 670, its a double pumper with vacuum secondaries. Also I have an electric fuel pump with pressure regulated at 7psi. And also I installed a new HEI type distributor for ignition.

 

yeah i was thinking of taking the cam out and reinstalling it straight up, but im too lazy, so first im gonna install the new holley hp 750. I went to dickmillerracing.com and he did an olds 350 build up and said he used a 750 with the same set up (except he ported the heads, mine are out of the box ) and he got 478 horsepower and 474 lb/ft on pump gas. Also i think youre right about the vac secondaries, my new carb will definatley have mechanical secondaries. Thanks. Oh and im definatley gonna step the gears up to probably around 3.25s, but i gotta get this engine staightened up first. thanks again.

 

And you have it backwards with the installation of the cam. You advance the cam to get more bottom end and retarded it for more high RPM power.
If you are running a stock GM (not aftermarket) HEI then the stock initial setting is 20° BTDC @ 1100 RPM with the vacuum advance disconnected and the source capped.
If you have a stock points distributor (which came in 73) then I would start at 8° BTDC and go from there.

Another reason it may seem sluggish is the Edelbrock heads were designed for use on a BBO even though they will bolt up to a SBO. The intake runners have too much volume to allow for good velocity with a small cubic inch engine. That's a lot of your issue along with the cam being installed retarded.

You need to open up the engine and get that straightened out or you're never going to be happy with the way it runs.

Also what kind of stall converter are you running? What rear end gears are in the car? All of this will play into how it feels.

 

So far, stock converter, no gears.

 

That's also a big part of it. That converter is holding you back big time. You need another converter probably in the 2200-2500 stall range and to get that cam timing changed. The rear is a big part of it too, but can be waited on for now. The gears will change how the stall works so when you get a new converter you're going to have to talk to someone to try and get something that will work for both. It's a compromise situation unless you just want to wait until you get the rear end set up to get the converter.

 

Thanks for the info, I'm gonna take all that into consideration. Ill keep you posted.