I have a 350 out of a 74 Laguna (pulled it from the yard). Anyways, its of the 2bbl variety. I'm getting ready to drop this into a 78 Z28 for my wife, and throw on a performer intake and carb that I already have.

My question is this - what were the engine specs of the 350 cu, 2bbl engine - specifically, the compression ratio and the cam specs. I'd like to figure out if since I have access to the valley if I should just swap cams or not...

Now, this motor is an older motor, but it was running when pulled. No smoke or anything. Ran smooth. Should I even bother since its for the wife ? I'm prolly gonna put a 3:73 posi rear in it and some 4 spd that I can get ahold of locally cheap.

Comments and/or opinions ?

Thanks,
Wayne graemlins/waving.gif

The 1974 L65 (350 2-barrel) and the 1978 LM1 (350 4-barrel) were almost entirely the same engine. The cam was the same, the heads were the same (1.94" intake, 1.50" exhaust). The block was the same 2-bolt main, cast crank affair. Chevy began putting hardend valve seats starting with the '73s, along with the EGR valve. Aside from the intake manifold differences (2 barrel vs. 4-barrel) I think the choke pull-off was different. Starting with the 75s Chevy went with the HEI big cap distributors (integrated coil starting in '78), plus the catalytic converter was used. This allowed the engineers to retune the carb and timing for better running since the catalytic converter would clean up a lot downstream.
One difference between the two versions of the 350, and one I found a bit surprising, was the compression. From 1971 through 1976 the 350 had an 8.5:1 compression, but it was dropped to 8.25:1 for '77.
The cam was the very common general performance cam that was used in 307s, some 327s, most 350s and the 400. The cam timing was 280 degree intake, 288 degree exhaust, 58 degree overlap, .410" lift.

Horsepower in '74 was 145 net for the 2-barrel, 160 net for the California LM1 4-barrel single exhaust, 185 net for the L48 4-barrel dual exhaust (Canadian Chevelles only for '74). Torque was 250 net lbs./ft. @ 2200 rpm (L65), 250 lbs./ft. @ 2400 rpm (LM1), 270 lbs./ft. @ 2600 rpm (L48).
Horsepower for the LM1 in '78 was 170 on regular Camaros (160 California) or 185 for the Z28 (175 Calf.). The only difference between the base Camaro & Z28 was the use of the low restriction exhaust on the Z28 (2.25 & 2.5" pipes, no mufflers but twin resonators). Torque went from a low of 260 net lbs./ft. @ 2400 rpm on non Z28 California cars to 280 @ 2400 on the 49 state (& Canada)Z28.

Where's that Laguna at? The front end clip, badges, swivel buckets and gauge setup deserve to be saved.

Cam, You know your details. I had a black '74 Lagina S3 in '75. The 350 in those were weak as delivered, but in terms of relateable power, going by the old gross HP ratings, with a 4 bar carb, the 8.5/1 350 was a 270 HP motor. I ran the '74 motor with the GM 327/350 hyd cam (222/222 @.050 .447/.447), 4 barrel carb and a set of 3.73's. The difference was like night and day. Took the motor to about 300 - 310 HP. Lot of better grinds today. But like most small blocks, they really wake up to a cam change.

Thanks for the info guys. graemlins/thumbsup.gif

That car looked to have been pretty much complete....including the nice hit it took to the front (although I've done worse and rebuilt it). I haven't seen it in the yard I got it from, but then again, that was last spring when I got it.

So a simple cam change would wake this up huh ? I have some time to do this.....so any suggestions ? I've been playing with BBC's for the past few years, so I kinda have fallen off the 'slightly over stock SBC' stuff....

I've always felt that the smog era ratings were artificially low. It has been said that if a '73 or '74 model car can run through it's entire operating range without a stumble, surge, or run-on, then it it not tuned to emissions specs. I recall them having a very distinct smell out the tailpipe, and one I have not experienced in a long time. (No, that's not what I've been smoking :D )

350CI motor with 8.5/1 CR. Probably anything with about 262-268 advertised dur and about 210 - 220 @ .050 (224 max). Lift at .450 max is plenty. Aftermarket intake with a 600 Carb, recurved distributor and a dual exhaust, set of 1-1/2 primary headers is plenty. For what its worth, this is basically the same motor as the L48 350-270HP version that came in the 71-72 Vettes. 76CC heads w/ 1.94/1.5 valves.

You will be surprised at how well one of these will run. It's not a big block or a stroker, so you don't get the big torque and it's not an LT1 with 11.0/1 and a solid don't expect to run it to 7000, but in a car like you are talking with a stick, this will be a good running 5800RPM motor.

Good luck.