I was looking for some informtion on porting the exhaust side of my sportsman II heads. I heard that they flow well on the intake side, but the exhaust side needs some work. Would a good polishing help these heads breath better? Or would something more extensive be required?

 

I have never heard of porting heads as ever being a bad thing.
My friend got about 20 horse out of porting his Sportsman II's
Polishing really won't do all that much

 

Mostly you need to streamline and contour the guide boss on the exhaust port. its huge as cast and blocks flow.

blend the bowl below the valve seats, smooth any rough angle on the short side. then you can polish the hell out of the exhaust port. The port exit is already pretty big
so enlarging is not nessessary.
You can do the same on the intake side but do not polish the intake port. Again exessive enlarging is not nessessary for a street motor.

 

Thankyou guy's for all the info! I also got some stuff on the heads from 2nd Gen. I was told to get the book by David Vizard about building SB Chevys on a budget. It Has alot of info on working these heads for more power. I'll defenately get it.

Here's another question. I have 1 5/8" headers on my car which are too small for these heads(flange restricts exhaust port). Do you think it would be better to weld around my existing headers and and remove the overhang on the flange or to get some new 1 3/4" headers?

 

Just a quick Hello,,I'm Back!

 

defently the 1 3/8ths.

 

hehe, i'm assuming you meant the 1 3/4? j/k....
Anyway, the sportsman IIs do flow well on the intake side, i didn't even touch the intake side on my first set (i've had 2 sets, my current set isn't ported at all). They should include instructions on these heads not to run them without porting the exhaust side, the I/R relationship is rediculously low. Just go ahead and make sure you port real good around the valve guide port, like F-BIRD said. You can polish the exhaust side real nice though, it'll help reduce carbon buildup. Just doing the exh. side will help you get the most out of these heads.

 

lol yeah.. 1 3/4ths i normally dont reread what i type.. sometimes i even type completely different words then i think i typed.. just the other day I was talking to one of my friends and i said to after forgetting something that I should have known I said "I wish my friend still worked" the word I ment to type was "brain", however that wasnt what I typed, she thought I was refering to errectile disfunction and became alarmed. haha.. dont do drugs, they rot your brain.

 

Dain Bramage! Me too.

 

lol

 

Sorry to get off the subject here but you guys seem to know a little about the sportsman II heads I have a 383 and was wondering if I should go with the 200cc intake runner or the 220cc The motor will have 11:1cr and eventually the HSR. Again I apologize Thanks Johnny

 

I'd go with the 200s as they come matched to a Fel-Pro 1205, and that's as big as you can really go on a HSR base. The 220s are matched to a 1206, and there aren't many EFI intakes that large, except maybe a mini-ram. That's the only reason i don't have AFR 210s.

 

What size of ports are on the performer RPM intakes for carbs? I have a weiand stealth intake, but really had to port out the openings to make it match my sportsmanII's. Would the RPm would probably be a better choice?

 

The port opening on the Performer RPM is smaller than the port opening on a Sportsman II head too.

Port matching required.

 

Cool Thanks!