I'm running big-valve heads w/64 cc combustion chambers on a 0.060-over 283 and the low compression combined with race-sized ports and large valves is making it a real pig to drive.

I gave the original power pack heads to my buddy 'cause they don't have the accessory holes that I need for the F-body.

I'm considering getting some 416 castings from a wrecker and freshening them up with new guides, springs and a valve job. I figure the 1.84 intake and 58 cc chambers should improve driveability.

Anyone have any experience with these heads? I figure they shouldn't be too hard to come across at the wreckers and won't cost a pile. Any known problems, or can anyone suggest another casting with similar attributes?

What about the aluminum 305 heads, are they getting reasonably priced in the used market?

 

There are no aluminum 305 heads.

The 416 is a decent casting for a small motor like that. Pocket-port them, and they'll flow enough to get about all you're going to get out of a street-friendly 283.

 

The 416 castings will work nicely to get your cr back up on a 283.
You may even want to shave them down to 55cc's to get your cr in the 9:1+ range. Look at your head gasket and see how thick it is. Factory 283's came with thin .015" head gaskets.
A thicker say .040" replacement will lower compression quite a bit. See how far the piston sits down in the bore when @ TDC.
This deck clearance will be around .025". As long as the deck clearance is .02" or more, use a thin head gasket.
This combined with a .040" replacement gasket and 64 cc heads
would put your cr right about 8:1.
58cc heads would raise that to 8.6:1
416's Shaved to 55 cc and a thin .015" gasket will get you 9.5:1
Just right.
A .030"/.035" cut off the 416's should do it.




Be sure to do the lil pocket port job as stated above by RB. Port match the heads intake openng to the manifold (not the gasket).
And just clean up the port walls without removeing much material.
This will get your some flow, but maintain port velocity for good throttle response. Do not polish the intake ports.

What camshaft are you running in the 283?

A 283 is real easy to overcam. If mileage and low end torque is a priority, I'd recomend and cam with less than 200 degs @.050"
intake duration. If your car has stock rear gearing and a low stall converter, this is the cam your looking for.
One of Summit Racing's mild budget hyd cams would be a good replacement.

Smaller is better.

 

415 casting heads work real good for boosting compression too. The set I have are milled to 52cc, with the bigger 1.94/1.5 valves. These heads were used on 267's and some 305's.

 

Depending on what cam you're using and if you need EGR, Vortec heads can work real nicely on a 283.

 

F-BIRD'88 you've essentially done all the same math that I've been playing with.

I have Edelbrock Al heads which recommend a Fel-Pro gasket with the wire ring, so I've been using them at 30-some thou thick. The deck clearance on these rebuilder pistons is heaps, maybe 40 thou or more, I haven't checked it with a dial indicator or anything. I suspect they are intentionally cast with lower compression height at 0.060" over to keep compression increases down, they're not intended for performance I guess.

Like you suggest I intend to shave the 58 cc chambers a tad and run a shim gasket with the iron heads and hope for about 9.5:1.

The same buddy of mine that I gave the original powerpack heads to was turfing his '80 Malibu with a 267 in it, I told him I wanted the heads off it but before I knew it the car had gone to the wreckers. They would most likely have small chambers and 1.73/1.50 valves, which is a good start.

The camshaft in there is a comp 268H, 218 degrees @ 0.050". It's a little lumpy in this short-stroke motor, especially with the horrid compression, but I'm running a wide-ratio V6 5-speed and 3.42 rear, so it works out okay. I've had consistent mid to low 14s @ 104 Mph from the G-tech Pro, so there is horsepower there. Problem is I think the torque peaks at maybe 4800 and the HP somewhere well over 6 grand!

Maybe with some more conservative heads and increased compression I can keep it in the mid 14s and make it a lot more driveable.

92RSFivePointSlow, how much did you shave your 415 castings? I gather they're holding up okay still? I'm assuming that they are originally 1.73/1.50s.

 

Rusty:

You'll have to decide what is important to you.

If you want to keep the horsepower then keep the heads
but mill them down to increase compression. What about pulling the motor and decking the block so the pistons come all the way to the top (0decked) or slightly above?
This along with a good head milling will increase the cr quite a bit. You can mill those heads quite a bit.
If you remove the Edelbrock heads and replace them with essentialy stock 305 heads, your compression will go up but unless you use big valves and fully port the heads like I do,
you bound to loose some horsepower.
If you really want more low end torque and mileage
and could put the Edelbrock heads to better use on another motor (350+ci) then pull the heads and cam for smaller milder stuff.

If you want a new cam, try this guy in BC. I've ordered some stuff from him, he's top notch. good $price$ to.
Got everything from mild to wild....

www.amotion.com
I'd go with some thing around 200 to 206@.050 if you can raise the cr. or 195@.050 if not.
Either that or throw in some 4.10's. In 5th you'll still cruise
at a very reasonable rpm.

 

Ah yes, decisions decisions...

I have an '81 vintage 350 that I've torn down to the shortblock and sitting on a stand to go with the aluminum heads. They need way more inches under them than the 292, plain and simple.

I have put a fair bit of money into the 292 shortblock (balancing, ARP bolts, ARP head studs) so I would like to get some money out of it or keep it. That's a big part of the reason that I'm interested in putting some freshened cast iron heads on it, so I can attempt to sell it as a running longblock, not an engine on a stand.

I'm getting older and more conservative by the day, so a smooth running engine with some throttle response and useable torque (and mileage) is more important 90% of the time than big horsepower. If I'm content with massaged 305 heads on there and it produces decent mileage and torque, I can run it.

If it runs like a short stroke motor with smog heads then I'll build a 10:1 350 that the aluminum heads deserve. I have a feeling that with another point and a half of compression and the increased velocity I will be happy with it.

I'll take a look at that link you sent right now...