Pictures of my head porting work

[sled_dog]

somewhere between 2 and 3 hours into this one head as of right now. These are factory heads off a 1989 or 90, 9C1 Police Caprice. I'm just doing my own portwork to open them up a little bit. Want my 383 to breath.

All I've done is radiused the edges around the valve, radiused the valve guides, removed ugly castings that stuck into runner, and gasket matched the intake runner. I will be polishing the exhaust side as best I can. I will likely polish the chambers as well.

Oh also, if you disassemble a set of these heads and run your finger along the "top" of the intake runner, where it meets the valve seat is a big lip. I smoothed that out so air can freely flow along the top and right into the cylinder (since air going in and out of the engine follows the roof of the port) .

 

[sled_dog]

Sweet I just bothered to run the casting numbers on them.

14101083

"Gen.I, also used on crate motors, 285 or 300 hp, 64cc
chambers, 72' center manifold bolt
angles"

Gives me hopes for my motor. 383 my port work, LT4 camshaft, headers, Edelbrock intake too bad I'm choking it with TBI.

 

[dontoe]

You do good work!

 

[HarryH3]

You're just getting started. You can take a LOT more material out of those ports yet. There's some pretty good info on porting to be found here:
http://www.sa-motorsports.com/diyguide.shtm

I've got at least 40 hours of grinding and sanding into the L98 heads on my K5....

 

[sled_dog]

I'm being conservative as I go. I need to go get a stool tomorrow, and just sit there all day.

 

[CyberSniper]

the seats could use some more time on them... don't be afraid to grind on them a lot to get them to blend into the head nice. I'd also spend some more time on the guides... you can take a lot more meat out of them. Most of the force applied to them is inline with the airflow so you can make them narrower and blend them more on the shallow side.

I didn't notice any difference between polished and not polished on the exhaust side on a pair of 305 heads I had flowbenched. So unless you're wanting to avoid carbon buildup I'd just leave it alone, it's a waste of time.

As far as farther up the intake... I'd just get rid of the high spots and make sure the transition between the intake and the head is moderately smooth... no misalignment.

I'd spend the most time gasket matching the exhaust side and making all the ports identical. Usually the exhaust side is pretty ****ty on Chevy heads for some reason.

I've CCed and polished the combustion chambers of a couple pairs of heads... really time consuming.

 

[sled_dog]

yeah I was just thinking I need to spend more time on the valve guides, polishing the exhaust side is just about prevnting lots of carbon buildup.

 

[JIM88K5]

Try choking your motor with a 750 cfm throtle body from XtremeFI.com

 

[beater_k20]

TBI heads... great for a low grunt 383.

 

[sled_dog]

TBI heads... great for a low grunt 383.

Did you bother to read the full post? They are not TBI heads. They are the same heads used on 300HP crate engines. Good job reading. The police car they came off of wasn't TBI either, it was Carburated, thats the way 9C1s were in the old body style.

 

[beater_k20]

14101083

"Gen.I, also used on crate motors, 285 or 300 hp, 64cc
chambers, 72' center manifold bolt
angles"

yes, i did bother to read the whole post. and after '86 i've never seen another carbed B Body come from Chevrolet.

 

[sled_dog]

Police Package

 

[rcurrier44]

Here is another good link to give you some ideas.

http://www.chevyhiperformance.com/techarticles/95518/index.html