383

Hey guy's Im building a 383 sbc, (stroker kit from summitt) I am using a 71 350 4 bolt main block out of a pickup, My question has to do with the heads, I have a set of #882 casting heads but after inspecting the 71 350 heads #336 the 71 heads look to be better castings..these heads are 76cc heads and Im going to try and machine these heads for 2.05x1.60 valves (along with a full porting) I know the #461 or 462 casting heads would be better But I plan or buying a set of dart iron eagles in the future, but being the hot rodder that I am, I still want this 383 to perform, which would be better the #882 or the #336? Im also going to use comp cams X-treme energy 284 grind, (hdy) And a professional products RPM intake, and my compression will be 10.0:1 using 76cc heads with the mini dome pistons I have, any estimates on the HP? and TQ? and this is going in a 90 S-10 pickup..Im looking to make around 400hp, and proboly 450 with the Iron eagles in the future, How close am I?


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I learned the hard way; 882's are rubbish!
My origninal set were screwed when I took them off before rebuilding, I got another set checked, magnafluxed, new valve guides etc. and they recently gave up on me as well.

Not sure about the 336's but if your planning on getting iron eagle's I'd not waste much money on them, if they look fine I'd just bolt them on for now and save up for the eagles quicker
For the price of porting, new valves etc. you'll be over half the cost of the eagles so just get the extra couple of hundred together and get them now.

According to desktop dyno, with heads like 462's (with 2.02/1.60 valves) you'll be running;
395 HP @ 5500 RPM
427 lb/ft @ 4000 RPM

with iron eagle 2.02/1.60;
440 HP @ 5500 RPM through to 6500 RPM
443 lb/ft @ 4500 RPM (over 400 from 3000 RPM)

your best bet is to get the aftermkt heads, but if you insist on the factory heads and you are going to have port work done, go for the 882's, their advantage being they flow better if port matched . and they have hardened exhaust seats, but if you go for 1.6 exhaust valves you will loose that. Also consider that mostly all the 70-80's GM castings stop flowing at about .480 lift, look at some of the web posted flow charts.

hmm, Id fall pretty short on the 400hp mark with the 336 heads then, thanks for the advise, consider me in the market for a set of aftermarket iron heads...the destop dyno is accurate with real world numbers and 440 hp is just where I want to be, and the torque! wow!!! Illbeit tracktion problems...


and thanks again guy's..

do you have a program to put different intakes on the desktop dyno? like edelbrock, holley and weiand?

I ran the 882 heads on my 383 before I had to rebuild it.


I put screw in studs, 5 angle valve job, etc. They did decent, the engine pulled quite strong all the way up to 5500.

If you're on a budget, these heads will get you by for a little while. Until you want more