I'm thinking about upgrading my 331 to a better set of heads than my current stock 416 heads? I'm running about 9.4 SCR and 7.8 DCR with the current 58cc heads and I am looking for better performance without loosing my compression with 64-67cc heads. i don't want to change to domed pistons. Does anyone make a good 58cc head? Didn't some of the corvettes of old run a high compression head? Any thoughts?

The small-chamber Vette heads are aluminum. Their casting # ends in 113. They came on the 87-up TPI motors. Being aluminum, they are required to have higher static compression than iron, due to aluminum's greater heat conductivity (cooling down the hot gas in the chambers). They are about equivalent to a 64cc iron head, as far as the actual efect of their compression, on a 350.

About the only ones are World 305 S/R Torquers. They're 58cc.

Are you familiar with the S/R torquers? How would they rate on the performance scale, low end or middle of the pack? How would they compare to the 416's I'm running now?

Dart iron eagle--49cc chamber and protopline 50cc chambers..I am using the protopline model..they actually cc'd at 54cc

Are you running four valve notch, about 4 cc flat-top pistons in your motor??

I ask b/c a .030" over 327 with 58 cc heads and the piston down in the hole .025" along with .038" thick headgaskets gives right at 11.1 to 1 CR. per ROSS's compression ratio calculator..

I know the .040" over 327 I gave my nephew with the same pistons and W/P's S/R Torquers at 67 cc's with big valves and .038"/.039" or whatever they are headgaskets was right at 9.95 CR...

And yes, I have been considering the 58 cc Vette aluminum heads b/c they are fairly cheap.

I figure my stock bore, flat-top piston, 283 motor with .038" headgaskets and .025" down in the hole pistons would be right at 10.19 CR.!!

pdq67

Im running the 58cc aluminum corvette heads on my 10:1 350 motor. also have a xe262 comp cam. The car screams on bottom end but doesnt have much up top. Its really fun to drive. My buddy was saying the other day he found some place around here that was selling them cheap.

Yes, I'm running the four valve relief flat tops. However, I was expecting about 0.025 down in the hole with the new pistons but they turned out to be 0.045". The factory makes them about 0.020 over to be conservative. Found that out too late or I would have shaved the block. I'm running a felpro about 0.041 thick so my quench is 0.086, really sucks. I was assuming the reliefs to be about 6 cc. Worked out to about 9.4/7.8 on the Pat Kelly SCR/DCR calculator. I just found the pro-topline irons on ebay(new)for about $750. They look like they would outperform the World S/R(305)heads.

If the Dart heads are in fact available yet, they might be a good choice.

I don't think I would buy Pro Toplines right this moment, until they get their problems sorted out or get bought out or whatever. It seems they're having trouble right now with a minor detail that may or may not be significant .... continued existence.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2469828195&category=33617
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2470705932&category=33617


Aluminum, 58cc, and much better than you have or a SR. You'll need new valve covers and do some work on the two center intake manifold bolt holes on each side.

Question???

Just much did the set in the lower link Greybeard posted get cut to get down to the machining locating squares in the combustion chambers???

.010", .020" or even up to .030"??? Or more???

Just trying to figure howe much the chambers have been made smaller, that's all...

pdq67

be aware on the Dart and protopline small chamber heads, the valves are .100 closer to the piston. This requires some valve relief work.

Greybeard,

Not trying to put you on the spot but how much of an improvement over the 416 stock heads? Are we talking 20-30hp and torque or more than that. I know it depends on all the variables involved but do you have a gut feel? I know you have a lot of experience with 283's and 327's. I have never had anything other than stock heads and I just don't want to spend $600 to gain 20 horsepower. I value real life experience 10:1 over what a desktop dyno tells me.

Clyde

Clyde,

I'm going to have to plead ignorance as to direct knowledge as I've never worked with the 416 casting other than look at them in the machine shop.

I have been able to do back to back with the L98 and Vortecs on a ZZ4, and there is lots of Vortec comparos out there. The L98 made more torque than the Vortecs and 6 less HP. I'd say the torque was a result of higher compression and better matching of the intake/cam. With the Vortecs we used the RPM manifold and it's ports have more cross section, skewing the results toward HP and giving up velocity and therefore torque. We never put the L98s back on so I've no later comparison when we got rid of the ZZ4 cam and started leaning on the motor.

My gut tells me there's a lot more potential in the L98 head than the 416. The 416 looked pretty tight in the intake port and I'd be real surprised to see any power figures over 300hp without port work. The L98 "potential" is over 400hp without porting. Thats not to say that your combo will see huge power increases. If you were to cam for peak power at 5500, I'd be surprised if the 416 gets with-in 35-40hp of the L98. Whats the Desk-top say?

pdq67: I think they must have milled the heads at least .020, maybe .030 to expose the pads like that. 53-55CC ?

I'm catching a plane in the morning, I'll check in when I get back next week.

Just curious what the full casting number is on the "416" head? Can't find it in my books.

Mike

305HO heads.

1980 to 1986 14022601’s are chambered like big valved double hump heads.

Whereas the 1980 to 1984 14014416's are like smoggers or big valved W/P, 305 Torquers...

"Bathtub vs D-shaped"!!

Hope this helps.

pdq67

Thanks PDQ!

Mike

I ask b/c a .030" over 327 with 58 cc heads and the piston down in the hole .025" along with .038" thick headgaskets gives right at 11.1 to 1 CR. per ROSS's compression ratio calculator..

I get about 9.93:1 compression with a -5cc flat-top, .063" deck and a 58cc chamber.

I'm looking into this b/c of my 283...

pdq67