Here we go with another can of worms. We just picked up a Chevy C-10 for Little Truckdoctor. It was his Grandpa’s truck and Grandpa didn’t need it any longer, so, now we have a new project. It’s a Small Block automatic, we have a GM crate stock 350 for it that I bought new 15 years ago and had in two other O/T Chevies. This truck will also get a 700R4 that I had rebuilt and was in an old Suburban with the above 350. The engine has maybe 15,000 miles on it and the transmission 5000. This is an 8.5 to 1 compression engine with 642 heads. My question is this, has anyone used the 151 cam with an 8.5 to 1 350? The 350 currently has a Melling MTC-1 cam with 204/214 at .050 and .422/.442 lift. I don’t know the axle ratio yet, but would guess 3.07. The rest of the long block is stock with a Holley Street Avenger intake that is an Edelbrock Performer copy. Carburetor will be an Edelbrock 600 and headers with 2-1/4” exhaust. The ignition is an Accel HEI distributor. Do you guys think the cam change will make any difference? I understand the L-79 had 11 to 1 compression, and that is really why I’m asking. Thanks for all of your help!
Sounds like an "off" combination to me with that cam. Things would be better with - 1. More like 9 to 1 compression. More would be better, but not with todays gas. 2. A gear ratio of at "least" 3.31. And being a truck, likely with a tall tire, a 3.55 gear would be the minimum to me. The 3.0 and 'truck" tire diameter is a BAD combination. Too tall. This reduces the overall ear ratio. The 3.07 and the truck tire would be like running 2.97 in a car...not good, at least for any sort of reasonable performance. 3. Not sure about that head. Needs to flow at least as well as the old 1.94" double hump heads. The manifold and carburetor sound fine. The HEI is good, as is the 2-1/4" exhaust. I ran that cam in a couple of engines back in the day. It works well, as long as the rest of the combination matches it. Mike
3863151 L79 327 - 350 hp HYDRAULIC Lift .440/.440 or .447/.447 both listed Dur @ .050 220/220 or 222/222 LSA 114 Comp cams grind 151H (.447 lift, 222 dur, LSA 114) The 350 currently has a Melling MTC-1 cam with 204/214 at .050 and .422/.442 lift. 151 cam has a little more lift on intake, about same on exhaust, with more duration. Has plenty of duration without much lift. 3.07 gear won't help a lot, but low first gear on 700R4 will overcome some of that.
This is similar to the 151, but has more lift, still a mild factory cam 3896962 L82 late 70's vette HYDRAULIC Lift .450/.460 Dur @ .050 222/222 or 224/224 LSA 114 Less duration to bring power band in early and decent lift for a driver 218 dur .050 .450 lift https://www.summitracing.com/parts/sum-1785/make/chevrolet Little more lift 218 dur .050 .458 lift https://www.summitracing.com/parts/sum-1065/make/chevrolet Very popular grind, 214/224 .050 .444/.466 lift https://www.summitracing.com/parts/sum-1103/make/chevrolet I ran the same cam with a 700r4 and 3.73 gear. 9-1 350, 70s smog heads. Much faster car than I expected it to be.
Why are you guessing 3.07 rear gear, I never heard of a truck with a 3.07 rear. All the one's I've seen are 4.11 to 3.73. You would be wise to check that out first. Pat
I don't know about trucks, but years ago, I had a friend who bought a new '66 Corvette with an L79 (327/350), a 4 speed, and 3.08 gears. The next year, I bought a new '67 Corvette with the same powertrain, except I ordered the 3.70 gears. His car was an absolute pig compared to mine; he even got beat by a guy with an Impala SS's with a 327/250 and a Powerglide! EDIT : In case somebody doesn't know, the "151 cam" was what made an L79 an L79, arguably the best SBC of that era.
Bob is that in early trucks (Pre 1970s) it seems counter to the purpose of a truck to have a gear that high. How in the world would it move a load? Pat
When I used to scour the wrecking yards seems the ‘60’s era Chevy 1/2 tons had 3.73 or 4.11’s, GMC’s had a wider selection from 3.08’s to 4.11’s. Not to say Chevy didn’t use other ratios, I just never came across them.
Will it run and drive ok, yeh. Will it make any horsepower, (or torque, which a truck needs), not a lot. As stated above, the 327 engine that the "151" camshaft was used in from the factory had 11 to 1 compression and it came in three different (p***enger car) platforms, the Corvette, Chevelle and Chevy II, with the Chevy II being the lightest and a C10 weighs a whole bunch more than even the heaviest of those cars. Another important point is no car was ever produced with this engine from Chevrolet with an automatic transmission behind it, and for good reason, mostly to ensure the engine stayed in its designed ("happy") powerband. It all boils down to what the truck ultimately is used for, spirited driving or hauling a thousand pounds of gravel and it won't do either very well.
My landlord stuffed a 350 in his 57 Desoto. Used the Crane cam version 151, flat top's with 76cc heads 1.94 intake valves, cast iron manifolds. It ran is the best we could say about it. Poor gas mileage, no real power, even if revved to 5800. Eventually pulled it and built what would be considered a 350 300. Ran much better, better fuel economy. More usable torque.
I ran that cam in a 327, if I remember correctly had 1.6 rockers on it. Ran the double hump heads with bigger valves, port matched the intake and exhaust manifolds ( ran 2-1/4 ram horns) 2000 stall and a turbo 400. Wanted it to look as stock as possible. Ran it in a 67 Chevy truck complete with 4:88 posi. Great truck stop light to stop light. Surprised alot of people. Gas milage ****ed ( who cared, it was a hot rod) and distance per gas tank wasn't good but again one of the funniest trucks I've ever driven !! Yep need compression and gears with that cam.
I had that cam in a 327, probably a bit more snappy than being in a 350. Better fitted with a manual trans or stall converter. It would tend to load up at stop lights with an automatic with stock converter. Compression is that cams friend...
If you want to use a cam from that era, the 962 would be a better choice over the 151. The 962 was first used in the 350/350 in 69, also an 11 to 1 engine. GM continued to use it in the "performance" version of the 350 for another 8-9 years as compression ratios dropped. I've had an OT 69 Vette since it was about 6 months old that came with the 350/350. In the late 70's it had about 90K miles on it and I pulled it down for rings, bearings, timing set and a valve job. The face of one lifter looked a little strange, so i figured I'd replace the cam and lifters too. Couldn't find a 962 at any of the local dealers, and for some reason they were out of stock at the zone parts depot too, so I went back with a 151. From about 2800-3000 rpm on up, I couldn't tell any difference between the 2 cams, but at anything under 2500 the 962 definitely pulled better than the 151 does. This is in a car with 3.70 axle and 2.20 low 4 speed and a curb weight of about 3200 lbs. If your son's C10 is from the late 60's early 70's era, depending on bed length,etc, it would weigh in the 3200-3400 lb range with a small block, so near the same as Chevelles and Vettes of the same era. Most people just sorta ***ume pickups back then we're way heavier than cars, but they weren't. I guess part of that thinking is influenced by all the 3 ton behemoths on the road today that people call pickups.
Once again the HAMB comes through. Thank you guys for all of your responses, you all verified exactly what I was thinking. The 350 runs well, and the current cam is fine and already broken in! I installed the current cam about 13-15 years ago, and currently am a little apprehensive about any more flat tappet cams.
The current cam is pretty good match for 3.07 gears. Should drive well, won't be a powerhouse, but mileage and drive ability should be very good with 700r4. If you come across a 3.73 rear itll wake it up. Let us know when you find out actual gear ratio.
That’s a great idea! I can sure install a 3.73, I’ll also add a Posi at the same time. It’s probably cheaper than a cam swap, without the stress of cam/lifter failure.
I personally think the 327/350 cam is very mild in a 350. I've run bigger cams in 350 and still stock converter. The specs on the 327/350 cam 222 degrees at 0.050 and only 0.447 lift is not a big cam. Sure higher compression works better. Works better in any engine, not just that cam. The real limiting factor on the crate engine is probably ****py heads. Depends on which exact crate engine, but unless one of the factory performance crates, the 260 hp and similar have poor heads.
'73 up. The point of the telling is that there were much faster gear ratios around in pickups. I've also seen 3.36. Which is a good ratio . Very similar to the Ford 3.50 ratio found in so many 9" diffs.
I would be more concerned with axle ratio than with a new cam. The small block with an OD and a 3.07 gear is not going to be a happy camper in that 4000 pound brick. The L-79 cam works well with 9:1 compression. I would probably not run it in an 8:1 compression engine. If that helps at all.
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