I've asked before and I cant seem to get a straight answer.

What do we need to look for in aftermarket heads to assure they will bolt to our intake manifolds?

I am building a 350 right now and am looking for a good set of aluminum heads for it.

I am running a stock TBI intake manifold on this motor.

I searched for "centerbolt heads" thru summit... and came up with these. EDL-60859

If someone can tell me if they definately fit, I will buy them.

-Jim

 

They'd fit, but I personally wouldn't go with those heads. You'd need new hardened pushrods and non self aligning rockers too. I'd be sure of what kind of compression I'd be pushing as well, you want a good amount with aluminum heads. They are also pretty pricey.

For a TBI 350 build, I really don't think you can do any better than iron Vortec heads, great bang for the buck. If you want extra power look at the Edelbrock E-tecs, those would be my choices. Because if you're building up a 350 and buying aftermarket heads, there is absolutely NO reason to keep the stock TBI manifold, it would restrict you A LOT.

 

Stick manifold has been bored... got it from xtremefi.com along with a bored 50mm TB, TB spacer, injector spacer, and 55# injectors.

 

Still isn't going to flow anywhere near as much as an aftermarket carb manifold with an adapter plate, or the Holley TBI manifold. The bores are not what restrict its flow.

 

If your willing to spend over a grand for heads, there is absolutely no reason not to go with big boy heads like the AFR's. They are still the best street head out there. You'd be crazy to reuse your stock intake with a built 350. I would look into a low profile single plane or find a way to stuff a performer RPM under your hood. What size cam are you going with?

 

i think the e-tecs are a good choice. flow #s are great. not sure if i would want a flow # that is TOO BIG however. higher velocity thru intake tract has benefits as well(TBI tuning?). you can get GM iron vortec now drilled/tapped for early intakes as well as high lift camshafts. $260-$360 each

 

Ronny-you can have great flowing heads that have a very modest port volume and good velocity. Dart Iron Eagles and GMPP Vortec and Fastburn come to mind.

 

Thats what I like about the AFR's they have great numbers in a relatively small runner size. AFR doesn't advertise their flow numbers like some heads, they harp on velocity. I dunno, I think once you get over a grand in price your splitting hairs in the 180cc catagory as to which head is better. Prolly less than 10 to 20 HP difference.

 

Why limit yourself to 180. My 383 is getting 230 CC intake runners and a 2.08 valve, plus a cam to support it. Well find out how it runs, hopefully this spring. I am looking for 350 HP to the ground and atleast 400 ft/lbs all below 5,800.

 

how about the sportman 2 heads are those worth it?

 

I dunno about 230's on an under 6 grand motor. The circle track guys that are runnin over 7500 still use 220's on their smaller motors (350-383). I really think you'll be killing low and mid range with that big of a head. It'll be interesting to see what your VE curve looks like.

Velocity is what builds torque. Your not gonna limit a 6000 rpm 350 with 180cc ports. IMHO they are the perfect compromise between all out power and good mid range and throttle response. Then again you know what they say about opinion's and a certain other body part.......we all have them and they all stink

 

Well I bought the heads thinking of running them on a 406, then I decided 383 since I can't find a good core 400 block and have a good barely used 350 block that is already .030 over.

They were on a 383 that would light the tires up in a 74 Lemans with a 3.08 or so gear.

 

Ohh they'll make power no doubt, I just wounder how much bottom end you would be loosing over a 200 or 220 head? I hang out on the hobby stock boards and most of those guys debate on going with either a 220 or 230 head. It kinda depends on the length of the track and wether or not they have somthing bigger than a 420...

They are also running cams with only .450 lift for rule reasons, and duration in the 250 to 260 range at .050 to make up for it. I almost bought a set of circle track heads off of a modified that were ported 220's, I decided against it only becuase they were milled till the heads were less than 1/4" thick. If their cheap, go with them. You might surprise some people.

 

I bought the pair for $750.00 with 5 hrs run time on them. I could sell them for more than that now. That is cheap in my book considering they are over $500.00 a piece and had a set of high dollar valves and springs in them. They also have comp cams guideplates, etc. They were also already drilled for steam holes and were on a 377.

The engine will be running a Comp Cams X4280-HR cam. One of the larger 4x4 grinds. I am hoping that by using a bored 454 TBI on the carb-TBI adapter and gasket matched RPM intake it will run good. Balancing fuel delivery will be a chore though.

BTW-the engine is only going into the van for a while. I have further plans for it farther down the road. Later it will get an even bigger cam and a big carb on it. It will be in a G-body or F-body after a while as a track only car. It will be a 6,500 RPM engine when it is all said and done.

 

Can't beat that price, I suggest a G-body