I have a 350 in my 75 Chevelle that is madd weak. The motor itself is solid, but it still has the old SMOG heads on it, etc (150hp stock).
I havent really done much other than put an Edelbrock performer series intake manifold and 4bbl carb on it, which could have been a mistake, who knows. It currently runs like shit, we’ve had multiple people look at it, and we think the carb is just too big, and it is currently jetted down as far as it can go.
I am not looking to build a drag car, I just want it to run right and have better power so it might actually be fun to drive. Its only a 2 bolt main, so I know its not goign to handle a ton of power anyway.
I am looking to probably go with some sort of 202 160 aluminum heads, a well matched cam, and headers. I will probably redo the exhaust with an X pipe and duals, but anything behind the headers can be after the initial budget is spent.
The car also has a 2600rpm (I need to check on that, but it should be close) stall converter in a TH400 transmission. Currently 308 posi gears, but would like to throw some 373’s in it eventually.
Heads and a matched camshaft isn’t a bad start. With a stall convertor 3.08 gear wouldn’t be that bad with a little more power. Parts list will depend on how much money you want to spend. Give me an idea and I can suggest a good head cam combo
A good set of iron heads would also be good,its a big car so the weight difference of iron vs aluminum isnt that big of an issue.You’d probably want to find something like this to bump up your compression…
alot of people run the comp cams 268XE cam and have good results,im running an edelbrock and its better than I expected,I’ve also ran a summit .465 .488 cam and it produced very good results on my motor that was stock (made by crane).
i have my engine out of the monte i may be interested in selling. It was designed by a friend at Edelbrock. All componets compliment eachother. 4-bolt main, Bored out, full roller Valvetrain, forged everything, Custom built Holley DP, Dart heads, ported polished…the works. Only 2500 miles on the engine.
sounds like my problem, I got old shit tbi heads on my 350…
get yourself a old pair of 202/160 heads and get a good cam with headers that’ll give you some nice power…I am in the market myself for 202/160 heads, I’ll let you know if I come across an extra pair, and you do the same for me :tup:
OK, well here is what I’m pretty much set on, although there could be a few minor changes.
Bow Tie performance Vortec Heads
Vortec Intake Manifold
Hot cam
Ceramic Coated headers
1.6 ratio rockers
2" carb spacer
This comes in a few hundred under my budget, leaving room for exhaust or possible changes in the kit.
I am not sure on the cam specs, this is all part of a matched kit from GM. After a brief discussion with Halas, he mentioned being able to go a bit more aggressive on the cam than the cam that would typically come in that kit.
Any ideas? I know that I cannot go beyond .530 lift with these heads, and I have been told that I should stick around 250 duration…
I would also like to upgrade to a “roller cam” setup… any ideas?
One last thing I need, is recommendations on exhaust. I love it loud and nascar-ish. I hear dual 2.50" with X-Pipe is best, although i dont know what to do for mufflers, and I cannot find anyone who makes Tailpipes for my car with some brief internet searches.
Iron Vortec heads are a great investment for a budget performance iron cylinder head. The LT4 hot camshaft is a hydraulic roller camshaft and the profile will be decent for what you are doing. However in an older block like you have you will need conversion roller lifters. Just the lifters alone are around $425-$450 so it is very pricey to go roller with an older style block. You can still run a hydraulic flat tappet camshaft and make good power. The GM LT4 hotcam kit is a bargin but that and the lifters will put you back a little under $1000. You can also get Vortec heads with upgraded valve springs to go over .530" lift. If you want any help just call me or send me a PM
Stay away from that crane 272 i ran it. duration at .50 is only like 216* way too small. i even tried the cam with 1.6 rockers and it didnt help much. find a cam with over 480 lift and duration at .5. of at least 224 you’ll be much happier
COMP XE268H-10
Duration @ 0.050" 224°/230°
Lift .477"/.480" with 1.5 ratio rockers
Lift .509"/.512" with 1.6 ratio rockers
As long as your valve springs and PTV clearance are okay I say go with the 1.6 ratio rockers. If you have to buy them anyways they are the same price. COMP has nice roller tip chrome moly rockers that are inexpensive for a budget build
2" carb spacer will add plenum/intake volume and will help with low end torque. It would be a great addition on a heavy car like you are building the engine for. Edelbrock performer is a nice intake. You might be happier with the Airgap Edelbrock intake however it is a good penny more $$$
Mufflers depends on what kind of sound you like and how much you want. Dynomax, Flowmaster, Spintech, Magnaflow and Hooker all have great mufflers. I purchase mandrel from spdexhaust.com They aren’t the cheapest but the quality is top notch and you have order different bend radius