Gage

Is the only difference between my motor and a 69 350hp 350 the heads and cam? Previous upgraded to petronix ign and added a "street" cam (doesn't remember specs)Edel Perf intake and carb. So if I get my hands on some 2.02/1/60 64 cc heads off a 69 vette/Z28 and add 1.6 roller rockers, do I have around 350hp at the flywheel. Just looking for suggestions from others who may have started with a stock 70s 350 and built it up with out touching the bottom end... Thanks in advance

verskel

Hmmm....that and maybe the pistons but I'm not sure on that.
Keep in mind that from '71 to '72 the Horsepower ratings are different for the same engine. You're headed in the right direction, though. ;)

stingraymaniac

have you the stock exhaust?
if so i should go for headers and true duals with x-pipe that would gain
some hp!! :smash: :smash:

markdtn

2 words FUEL INJECTION. Add TPI to your stock bottom end and you will think you added permanent nitrous oxide.

Gage

I have factory style side exhaust. Too much $$ and trouble to convert back to regular exhaust, plus I like the look and sound of the sidepipes. I had headers on my 427 69 a few years back and my impression is that anything that gets that hot on a plastic car is dangerous. When someone hit me, it shoved my floor pan into the headers (only 1/2 in clearance to begin with) and it caught fire. Luckily I had fire ext handy. They make for hot feet as well...insulation helps a little, but still too hot.

LOTAHP

The "J" engine (L-48) which came in my '73 was rated at 190-200hp. GM built "LOTA" different 350s and the biggest difference from one to the other, first was cam, then pistons, then cyl. heads. For example you can have the same 350 engines and one is rated 270hp, 300hp, 350hp and they all used the same cyl. head & pistons. But then take for example the LT-1s '70(370hp), '71(330hp), '72(275hp) and the only difference are the pistons (compression ratio) same solid lift cam and cyl. heads. It all come down to COMBINATION.


[Modified by lotahp, 3:15 PM 4/2/2004]

mrvette

Markdtn there is totally correct, just add headers, and an O2 sensor in the pass collector, and bolt on a TPI system, and forget the rest....

car gains a nice jump in HP, and driveability, and also with these small tanks....

FUEL economy DOUBLES, did for me, my mild cammed stock but rebuilt L48, '72 engine went from 12-14 mpg to 18 in town and 24 on the road....no other changes....NONE....

and the damn thing was running well/right also before that,....

TPI can support allmost 400 hp also....with large base/runners/proper cam/headers

GENE

Gage

thanks for the advice...Didn't buy the C3 for decent fuel economy, and while fuel injection may legitimately be helping hp, putting Elec fuel injection on a 30+ yr old classic just doesn't sit well with me. Just my opinion.

Gordonm

I just helped a friend on the forum with his L48 stock motor. We used to call it the TURD. He put a set of 180 AFR heads and a 262 Comp Cam in it with a set of true 1.52 roller tip rockers. Also added a set of headers and he already had a good set of mufflers and pipes. He was running in the 15s stock and he should be in the mid to low 13s on street tires. We figure around 350 to 370 HP when tuned up correctly. We did not touch the bottom end of the motor. I'm going there this weekend for a final adjustment of the lifters and if the weather holds out we will burn some rubber. It is an automatic and he also put in a slightly higher stall converter. Should be a nice driver now.

Ironcross

A nice camshaft from the LT1`s {1970} for a solid lifter cam to spin it to 7000, or if your not convinced on a solid lifter cam, the next best thing is the 1967 327/350 hp hydraulic cam. GM 151. :thumbs:

standup

:iagree: .........I'm running a similar setup with 9.3:1 compression and stock exhaust manifolds........the compression on a '69 is a lot higher than a '72.....

BTW....Gordonm......nice Vert :thumbs: