68hemi

I will be building a stealth 383 for my 57 and I want to run my staggered bolt pattern 9 fin valve covers. It seems I will have to use the 283 heads to do this. Can these heads be ported out to flow like worked 327 heads? I would have the big valves put in of course and pocket ported etc. I will be running 2 1/2" exhaust manifolds and exhaust.

MikeM

You're wasting your time.

68hemi

Why do you feel it necessary to comment like that? If you don't have something useful to say don't say anything. Your comment has no value to this thread.

I want to maintain the original integrity LOOK of the 1957 under the hood as close as I can and have more power than the underpowered base engine the car currently has. Is that a bad thing?

I know there will be power sacrifices with what I am doing and I could do it much cheaper, easier and have more power if I stuck a built 400 small block in it.

cardo0

Brezezinski racing does a whole lot'a cast iron head performance work :https://www.castheads.com.
They are not cheap but quality has a price.

Let us know what you decide.

BTW they port iron exhaust manifolds to.

68hemi

I really need to have a local machine shop do this work as shipping cast iron heads back and forth across country is too expensive.

I would just like to have an idea of what has/can be done with these heads.

I used to have a good hipo machine shop close by but te guy retired, sold all of the equipment out of state and moved away.

Scott Marzahl

The biggest valve is from a 305 chevy that will fit in those heads, not much for a 383 unless its a very mild one.

68hemi

Maybe I am better of trying to figure outa way to attach the staggered bolt pattern valve covers to a better head?

AZDoug

Tom parsons, DZAUTO, can probably help with that, IIRC.

I believe those heads you Have , use 1.72" intake valves and 1.6" exh valve, no way will they fit a 2.02" intake valve.

Doug

68hemi

Maybe I can just drill and tap 350 or aftermarket aluminum heads to use the valve covers? Has anyone ever done this?

MidShark

You could just shelve the 9-fin covers and get a set of mid-year straight across 7-fin covers which would open you up to some big valve head possibilities. On my '57 2x4 engine, I used a pair of '60s 327 heads that still had the pyramid on them and had bigger valves than the '57 heads would have. The valve covers have the straight across pattern, but 99% of lookers (or more) would never catch that.

MikeM

Now you're talking but you didn't ask that in your first post.

AZDoug

Here are some 9 fin covers installed on a 400 SB.

The ends of the heads have been faked to look like 1956 heads, also, IIRC..

Doug

https://www.corvetteforum.com/forums...-the-56-a.html

427Hotrod

That is definitely the way to go. A 383 will be strangled by a small head and there's a good chance a higher revving 283 could show its taillights to the 383.

We disguised a set of Dart aluminum heads to fit a 400" build. Filler bolt holes, rounded corners, epoxied diamond on the ends, made a hidden breather at the rear of them. We heavily ported a 283/270 2x4 intake using WCFB's (it still strangled it- but we made 500 HP with it).


How are you handling the balancer? Does your block have dipstick on correct side? What are you doing for breathers?


JIM

68hemi

Thanks Doug. I just sent him an email.

65tripleblack

That's a better idea, no question about it.

Brzezinski has already been mentioned. Top notch but expensive.

If you buy a set of used 462 heads, they will hold up to more extensive port work than 461 heads, which came with 2.02/1.60 valves.

It's a crap shoot with any vintage iron head as to how big you can make the intake runners, and since you'd have to "camofloogied" a pair of better 462s, you would be well served starting out with a set of Dart Iron Eagles which can be "camofloogied" by Brzezinski to look like your original '57 heads...................including milling down the valve cover flanges, heating in an oven, bronzing in new bosses for the staggered bolt pattern, cooling and machining. They will look "almost" like originals.

I recommend starting with at least 180cc intake runner volume.

JAYSUS CHRISTI YUMPIN YIMINI.....I just read post #9 . You aren't looking for stealth, you're only concerned about using your 9 fin covers. That changes everything. Buy a set of aluminum 210 cc heads. Have someone TIG weld some boss material onto them for your covers. Drill and tap them, paint them Chevy orange........................and you're done. Easy peasy and you'll have a fire breathing 383.........UNLESS...................you also want to install your original intake and carb(s). In that case, time-out, reset, start over, back to square one. If you build your stroker motor with the 1957 intake and carb(s) then you'll have stump pulling torque and I'd recommend using your 1957 heads with no modifications. Your 383 will peel the skin off your tires and have stump pulling torque...................but............ ......it will lay down at anything over 4000 RPM, maybe less. Your Corvette would make for a wonderful snow plow, tractor, or maybe even world class locomotive.

65tripleblack

Hey 68 Hemi,

Why don't we hit the reset button, OKAY.

Just tell us exactly what you want to do so we are not all taking pot shots and shooting each other in the foot.

You're apparently starting with a 327 block, right? If that's the case, then bore size limits you to a 2.02 intake valve. You are precluded from the advantages of a 2.05 or 2.08 intake which would be very effective with a 4.125 bore size.

What other considerations are important to you in trying to maintain your build as a "stealth" 283 from 1957? Block numbers? Dipstick orientation? Intake? Carburetor(s)?

You want to fool everybody with a stealth 383 for your '57, yet you give USMC 0802 grief in this thread:

https://www.corvetteforum.com/forums...post1594129703

DZAUTO

The last year for heads with staggered bolt pattern for valve covers was 1959.
Thus, your choice for heads will be 57-59 heads. ALLLLLLLLLLLLLLLLLL staggered bolt pattern heads had 1.72/1.5 valves.
THERE WILL NOT BE ENOUGH MEAT IN THE SEAT AREA TO OPEN THEM UP FOR 2.02 VALVES-----------------AND VERY DOUBTFUL EVEN FOR 1.94 INTAKE VALVES. But no issue going up to 1.6 exhaust valves.
From everything I've learned over the years, you can successfully open a head with 1.72 valves to 1.84 intake valves (such as a 3.05 head). With a set of 1.84/1.6 valves installed, some GOOD bowl and intake runner work, this kind of a head will flow quite well. Yes, WITHOUT QUESTION, it's going to cost some money, but you would end up with a set of real staggered bolt pattern heads. NOW, WITH THAT SAID, KEEP THIS IN MIND ABOUT THE HEAD BOLTS!!!! The 55-58 heads used only TWO lengths of head bolts. In 59, THE VERY END BOLTS (under the valve cover) were shorter (commonly referred to medium length bolts). Thus, all 59-later heads used 3 different lengths of head bolts. SOOOOOOOOOO, if you choose to go with something other than a 57 head, be sure to check the end bolt holes for the proper length of bolt.
Personally, I would NOT discourage you from trying to upgrade a set of 57-59 heads for a 383 build.
And yes, for a 383 engine, a set of heads with 2.02 or even 2.05 valves and larger intake runners (such as 195 or 215cc) would certainly flow even more.
But I'm only trying to provide specific answers to your question about modifying 57 heads to improve flow----------------IT CAN BE DONE---------------------IT'S ONLY $$$$$$$$$$$!!!!

MOST LIKELY, most of the guys here don't go back to the late 50s-VERY EARLY 60s when we had to work with whatever was available to build a screaming 301 (327 didn't come out until 62).

vettsplit 63

jim- when you were talking about the breather, didn't you have a pretty trick setup to vent your SHP block? I am very interested in that.

68hemi

OK, let's start over.

Here are my plans for the engine. I will start with an older 327 block with draft tube. Stroked to a 383 10 to 1 comp. Hydraulic cam with a 5800 red line worked, 350 heads or aftermarket aluminum, balanced and blueprinted, 2 1/2" rams horn manifolds and exhaust system topped of with cloned 270 h.p. dual quads. Yes, I know I will be leaving h.p. on the table with this set up but it will look like an original 28/270

Chuck Gongloff

What's wrong with these... adapters to run staggered covers on standard heads.

These have been around for years.


http://www.ictbillet.com/55-59-265-3...r-283-543.html