I'm in the process of building a 383 Stroker and I'm trying to select the right heads.

The requirement is to make as much power as possible while keeping the car streetable. To put things in perspective, I don't plan on any trips to the track. If I had to make a tradeoff, I would opt for low-end torque over hi-rpm horsepower.

The car is a 71 convertible, with a 3.55 rear end, and I plan on installing a TKO-600. I'll be keeping the original engine in the corner of the garage, so orginal appearance of the stroker motor is not a requirement.

Lastly, I'll be using an LT-1 hood to get a bit more clearance for the intake - I should be able to fit a peformer RPM or RPM air-gap without problems. Also, I would really like to avoid header issues and stick with 2-1/2" Ram's Horns exhaust manifolds - although they'll be opened up a bit.

In order to keep the car streetable, I'm leaning towards a Comp Cams "XR276HR" hydraulic roller camshaft with the following specs: Duraton @ 0.5 = 224/230, LSA = 110 and Max Lift w/ 1.5 RR = .502/510 Vaccuum approx. 12" Hg @ 800 RPM.

From what I've read and given my contraints, I am probably fine with heads that have intake runners of 195cc or less. In the Aluminum category the AFR 180cc appear to be ideal; however, given the Ram Horn exahust, I doubt I'll be able to take advantage of their flow capabilities.

I'm not opposed to using Iron heads, but have heard mixed reviews on Iron Eagles, Vortec's and Vintage Fuelie heads.

I have an opportunity to get a very nice set of Camel Hump "186" heads that would be fitted with 2.02/1.60 valves, and was interested in opinions regarding these or any other head options with my setup.

Any input would be greatly appreciated - Thanks in advance!

 

i have the afr 195 heads. they are an exellent choice, but they do like high rpm's...

 

Only issue with headers is more power! Dynomax sells coated headers for under $250. If you are going to use the rams horns you might look at a shorter duration came since you will not be able to fully utilize it.

 

Definitly go with headers. That cam is very mild for a 383 build. The AFR 195 heads are an excellent choice. The 180s will be small for a 383.

 

You might consider a dual pattern cam to help out the exhaust side. They were designed for that purpose.
TJ

 

The 186 Camel humps are great heads for an iron factory head they are the best. Votech supposedly flow better but the drag racers have been pulling better than 600 HP out of those 186 heads for years. With the ram's horn exhaust they are an excellent option that will give you tons of low end and midrange torque due to the higher velocity runners compared to a 195 or bigger. The AFR 180 is a better option but you are right about not realizing their full potential with ram's horns however the increased flow on the exhaust side of that head can be better used if you go with the split duration cam you choose with bigger lift and duration on the exhaust side to give the exhaust a little more time to get out of the ram's horns. If you look at the flow numbers The AFR 180 heads flow better than a lot of the competitors 195 or 200 cc heads and you don't lose the bottom end because ot the bigger runners. If you can afford them the AFR 180 is perfect for a streetable performance head for your application.

 

I have a 72 convertable with 383, comp 270HR(one lower than the one you are looking), pro topline 180 heads. I am using 1.6 rocker though which gives me little more lift(which the toplines like). I have always planned on using the AFR 180 heads in the future, but I wish I would have gone with the 276HR(my engine builder talked me out of it saying that I might not have enought vacuum). I can tell you that my vacuum gauge read about 16-17Hg's around 800-900rpm which is plenty. Thus I really like the combo you are looking at, and I think the AFR 180's would be great. I also agree with the others that you really need the headers to take full potential of your combo. Of course you could always upgrade later. By the way I am using the dynomax coated headers too.

 

Given my current contstraints, there appears to be some concensus on 186 heads and the AFR 180's. There is also some good feedback on Dynomax headers.

If I change course, and go for headers instead of the Ram Horns, do the AFR 180's w/ the Comp Cams 276HR still make sense given my intended use?

If so, besides ground clearance, starter motor heat/fitment issues, A/C bracket issues, and custom exhaust work, is there anything else I need to consider when going with headers?

Thanks.

 

Yea more smiles on your face due to more HP.
I would stick with the more modern heads. The 186s were good in their day but the new casting are way better than the older ones. Besides with aluminum you can run higher compression. The cost of redoing 186 heads vs. new ones is going to be close.

 

Thanks - I know the headers will give me a boost in the power department. They will certainly allow the 383 breathe much better given modern heads and a decent cam.

Unfortunately, I have recieved so many negative comments on headers regarding ground clearance, heat, and installation that it makes me start to doubt their benefits in a street-only use vette.

Perhaps that's the dilemma I will ultimatley need to resolve.

 

Definitely go coated on the headers. The car came with some headers that were not coated, and in the summer time it would about burn your feet. I bought the jet hot coated dynomax and it was a world of difference. I doubt they keep the heat out like ram horns, but they are much much better than non-coated. I believe someone else on the forum talked about re-cuaking(spelling?) the insulation in the vents to help with heat too....I'm going to look into that as well...sorry getting off subject.

 

The AFR 180 heads are perfect for your combo with or without headers.

 

 

You can go with a LOT more cam! I'm not even close to an expert or wise enough to recommend one but I know that my stroker has a much more radical solid flat tappet cam and is very streetable.
Lunati 40136 Mechanical flat tappet .543int/.561exh, total dur 288int/298exh, @ .050 249i/259e, 106 deg. centerline
I've got Canfield aluminum heads: 65cc chamber, 210cc runner, 2.08/1.60 stainless valves, 1.5 ratio full roller rocker arms

I haven't had this combo dyno'd but it should be in the mid 400hp range and right around 500lb/ft torque. With the same heads but slightly less radical cam it dyno'd 333hp/415lb/ft at the rear wheels.
Good luck!

 

The cam and type of intake have much more to do with how a motor runs. I didn't want to go overboard on my first 383 so I settle for Dart 215cc with the larger valve option. As delivered ported they were actually 221 cc. Later on I even went to bigger heads and larger cam.

165 cc double humps are for people still in the sand box. I spent lots of money to make them the best they could be and it's cheaper to just buy a set of iron eagles that flow much better and have modern chamber designs.

the 180 - 200 cc your still in grade school.

the 210 - 215 your about in highschool.

 

I vote go to high school too

Bigger heads > 200cc ( I ran 200cc heads on my 355ci )
Bigger cam, I am a fan of the solid roller but if you want to stay HR bump it up a few levels. THe bigger cubes of the 383ci will handle bigger cams.

Go with header, I don't know who you have been talking too but most on this forum have headers.

And a final note, I know the chances of you doing any of the above are slim at best but eventually you will see that people like gkull know what they are talkiing about.

I am not saying any of the advice on smaller heads is wrong, just from my own experience you can go big with properly matched parts and get what you want as far as power and driveability are concerned. Take a look at my sig, my 406ci has 219cc heads and that motor is nothing but fun to drive on the street and would still shut down most street/strip cars at the drag strip.

 

Motorhead - Monty (on this forum) built his 383 before I did and he used the AFR 210 CNC. So I already knew that 221 cc wasn't that much bigger and I wanted higher CFM of air flow.

Monty later graduated from High School with honors and bought Dart 18 degree heads with shaft rockers for his first 427 small block.

 

Since you said appearance is not a problem, I would use headers. There is no reason to restrict yourself with ram horns. The cam is mild, but it is still in need of headers. You could get away with a bit more durration like a 230/236 cam.... even that is mild for a 383. There is no reason a 230/236 cam would not be streetable. You will have extra low end torq from the 383 to make up for the cam. Not using the 383's displacement to your advantage defeats the purpose of the extra cubes.....

A 230/236 ish cam or larger would not be over kill and you will definately have pleanty of streetablity

 

186's are great heads to have ported if you can get your hands on a cheap set or already have them. If you are starting off on a clean slate, I would go aluminum... AFR 195's with at lest the 274HR... Call AFR and Comp too .. but know that the tech guys are Hit or Miss... if you get a bad tech guy call back multiple times if you need to.

 

I have never had a problem with clearance. These cars are full of room, especialy if you go with mid length headers. I have had manifolds, mids, long tubes, and hooker side pipes with out any problems