this is a question for a friend> he has a late 70s 350 engine from a camaro, not sure of the year but it has the oil dip stick on the driver side. he is wondering what the potential of 70s 350 engines, can they be fast with mods?? whats the deal on these engines??? is it woth putting work into?? oh and the engine was rebuilt not to long ago but car got wrecked so he took the engine.
any info would help us out alot, any up and down on them???
thanks

 

well from what i know is that in the 70s they didn't have the same emissions if any as they have now, so stock the compression ratio was much higher the late 70s or 80s engines... so stock pistions and a pair of good heads, cam, intake, and carberation...

400hp+ is very easy.

 

Actually, hp went down the drain in 1973. Anything after that up until the L98 and LT1 engines are going to be very weak with very low compression in stock form.

However, if you plan on modding it anyway, the blocks are just as good as any gen I 350 block to use. And if it came out of a vette ( or amybe a few other models) you may have a steel crank. Swap out the pistons, for some nice flat tops or low dome pistons to boost compression. With the plethera of aftermarket heads avaliable today realatively cheaply I dont recoment pissing around with the stockers.

If your going the budget route I would suggest a set of worked over Vortechs. I think they acn be had ready to bolt on for about $500-600 and they will be a huge advantage over the stock heads. Plus Im pretty sure you can get them with 64 cc chambers so your compression wont be crap. Topped off with a Vortec compatable intake ( An Eddy RPM or something) a nice carb, and a decent cam (Im sure the stock one barely makes .400 lift if that) And she should move well enough. I dont want to list any approx HP numbers because it would depend ont eh heads you went with and cam choice. But at teh very least you should be spitting out 325-350.

 

These are the 350 Motors that came out in 1970


L-65 350 | V-8 | 4.00 x 3.48 | 250hp @ 4800 | 345tq @ 2800 | 9.0:1 2V

L-48 350 | V-8 | 4.00 x 3.48 | 300hp @ 4800 | 380tq @ 3200 | 10.25:1 4V

Z-28 350 | V-8 | 4.00 x 3.48 | 360hp @ 6000 | 380tq @ 4000 | 11.011 4V

 

Thats irrelevant, he said the guy has a Late 70's 350 ie, 1977-1979. Yeah some of the 1970-1972 350s were pretty powerful from teh factory, but that all ended in '73

 

Late 70's 350 = crap.

 

Here are the options......

LG3 305ci/140HP V8 2BC - 1976 - 1979
LG4 305ci/155HP V8 2BC - 1980 & 1981
LM1 350ci/160HP V8 4BC - 1974 - 1981
L48 350ci/200HP V8 4BC - Horsepower varied, considered performance engine.

 

L48 is a base 350, L82 was the performance variant. Some time in '75 or '76, Chevrolet went to a lighter casting block. The earlier ones are the more desireable. The same time they went to a lighter casting they changed the paint color. Orange=good, blue=less desireable. Either configuration was availbable with 2 or 4 bolt caps. L82 was a 4 bolt block with a steel crank and forged pistons, if the block that you have is from a Camaro later than ,74 it is not likely 4 bolt, will not have a steel crank, and the heads are not equipped with 2.02 valves. The motor is still good working material since it has a 4"bore but by the time you invest in all good internals, you can get a crate motor with those same internals for the same or less money. If the motor still runs good all it needs is a cam to wake it up a little, since the cams in that era were not performance minded.

 

Some of the late 70s 350s are the desirable 3970010 blocks, with the 010/020 numbers indicating high tin/nickel content.

I'd have no issue with using stock parts from my '80 to push the 400hp mark. Stock block, rods, and crank are perfectly acceptable for streetable horsepower levels.

I'm getting ready to do a rebuild on my nearly 25 year old stock bottom end. After 250+ drag passes in the 13s, towing a Sea Doo trailer for a couple of years in 6th gear, and occasionally abusing the engine, it's staying together just fine. I'm doing the rebuild mainly to further raise the compression above what is doable with the stock, cast LM1 pistons.

So, some Speed Pro Hypers, zero deck, ARP rod and main bolts, and a good, streetable hydraulic roller cam, and I expect high 12s, and low-mid 20s MPG for the next 75k miles.