Home ported Sportsman II heads

[6.50camaro]

Just got back from first outing to the track since June 2020. { bat flu , move from La./Tx. border, remodel new place , help daughter with her new place} its been a long 16 months with no track time . In another post stated that I had a set of W/P sportsman II given to me . I said that I might get them flowed but that don't happen .Instead I bolted them on my 421 flat top 6.50 index motor to see how they perform .
Off the trailer with a base tune of 35* adv. and what I hoped was a safe jetting on my 1000 cfm race demon carb . It went 1.41-60' 6.46-1/8 @ 104.87.
The second run after a hour cool down and pulling a plug to check the ground strap for timing . I retarded the timing a touch {didn't put a lite on it just gave it a little nudge.} 1.371-60' 6.409- 1/8 @105.28 ran it out to 1000' and went 8.474 I have to much gear in it to run out to the 1/4 . it did coast to a 10.507 1/4 .
3rd run was off a little ,I might have over heated the tires or it was just starting to sprinkle and the 60' drop to 1.452 6.499 1/8 @105.06 performance .
So all and all I'm pleased with the performance I just wanted to see If they would run 6.50 in the 1/8 .

[mag2555]

What heads where you running before this and what where you shifting at then and now?

[steve cowan]

Just got back from first outing to the track since June 2020. { bat flu , move from La./Tx. border, remodel new place , help daughter with her new place} its been a long 16 months with no track time . In another post stated that I had a set of W/P sportsman II given to me . I said that I might get them flowed but that don't happen .Instead I bolted them on my 421 flat top 6.50 index motor to see how they perform .
Off the trailer with a base tune of 35* adv. and what I hoped was a safe jetting on my 1000 cfm race demon carb . It went 1.41-60' 6.46-1/8 @ 104.87.
The second run after a hour cool down and pulling a plug to check the ground strap for timing . I retarded the timing a touch {didn't put a lite on it just gave it a little nudge.} 1.371-60' 6.409- 1/8 @105.28 ran it out to 1000' and went 8.474 I have to much gear in it to run out to the 1/4 . it did coast to a 10.507 1/4 .
3rd run was off a little ,I might have over heated the tires or it was just starting to sprinkle and the 60' drop to 1.452 6.499 1/8 @105.06 performance .
So all and all I'm pleased with the performance I just wanted to see If they would run 6.50 in the 1/8 .

have they been rubbed on??

[6.50camaro]

I was running a old set of Dart 220 race series heads 64cc chamber 2.125in 1.625 ex that had Darts super mod 230cc or so porting . the cam is a Erson solid roller 260/268 @ .050 .675 in .645 ex lift . 850 holley HP carb . shifting @ 6600-67000 best that went was 6.31 but I never really pushed it to see if it would go quicker because I'm really only set to go 6.41 safety wise . {don't have full cage just 8 point rollbar} .
New combo shifted at 6600 still. Same short block and cam different heads , intake and carb. new heads are 70 cc chambers Dan

[6.50camaro]

Yes , Steve they've been rubbed on . stock 1.70 intake throat is now 1.83 with 2.055 valves the stock 1.299 ex throat is now 1.42 for a 1.60 valve. The guides have been trimmed down bowls have been opened up and reworked for good cylinder wall side port bias , pinch opened to 1.10 x 2.20 ,manifold opening 1.25 x 2.25 . chamber opened up valves unshrouded . A big thing I feel was the .460 reach plug was 2or 3 threads back in the spark plug hole. I relieved the chamber wall back till the end of the plug was flush with the chamber . also using an NGK projected tip plug . Flat milled back to 70 cc giving me 11.0 to 1 down from the 11.6 with the dart heads the ports pored around 226 cc . Did my own 4 angle valve job with a Toledo EZ eccentric stone grinder

[1980RS]

Just got back from first outing to the track since June 2020. { bat flu , move from La./Tx. border, remodel new place , help daughter with her new place} its been a long 16 months with no track time . In another post stated that I had a set of W/P sportsman II given to me . I said that I might get them flowed but that don't happen .Instead I bolted them on my 421 flat top 6.50 index motor to see how they perform .
Off the trailer with a base tune of 35* adv. and what I hoped was a safe jetting on my 1000 cfm race demon carb . It went 1.41-60' 6.46-1/8 @ 104.87.
The second run after a hour cool down and pulling a plug to check the ground strap for timing . I retarded the timing a touch {didn't put a lite on it just gave it a little nudge.} 1.371-60' 6.409- 1/8 @105.28 ran it out to 1000' and went 8.474 I have to much gear in it to run out to the 1/4 . it did coast to a 10.507 1/4 .
3rd run was off a little ,I might have over heated the tires or it was just starting to sprinkle and the 60' drop to 1.452 6.499 1/8 @105.06 performance .
So all and all I'm pleased with the performance I just wanted to see If they would run 6.50 in the 1/8 .

What kid of car are we talking here? your work and performance is most impressive.

[6.50camaro]

Its 72 camaro , leaf spring caltracs bars 3200lbs. Dan

[steve cowan]

Yes , Steve they've been rubbed on . stock 1.70 intake throat is now 1.83 with 2.055 valves the stock 1.299 ex throat is now 1.42 for a 1.60 valve. The guides have been trimmed down bowls have been opened up and reworked for good cylinder wall side port bias , pinch opened to 1.10 x 2.20 ,manifold opening 1.25 x 2.25 . chamber opened up valves unshrouded . A big thing I feel was the .460 reach plug was 2or 3 threads back in the spark plug hole. I relieved the chamber wall back till the end of the plug was flush with the chamber . also using an NGK projected tip plug . Flat milled back to 70 cc giving me 11.0 to 1 down from the 11.6 with the dart heads the ports pored around 226 cc . Did my own 4 angle valve job with a Toledo EZ eccentric stone grinder

sounds like you have done well with those heads
nice job

[steve cowan]

Yes , Steve they've been rubbed on . stock 1.70 intake throat is now 1.83 with 2.055 valves the stock 1.299 ex throat is now 1.42 for a 1.60 valve. The guides have been trimmed down bowls have been opened up and reworked for good cylinder wall side port bias , pinch opened to 1.10 x 2.20 ,manifold opening 1.25 x 2.25 . chamber opened up valves unshrouded . A big thing I feel was the .460 reach plug was 2or 3 threads back in the spark plug hole. I relieved the chamber wall back till the end of the plug was flush with the chamber . also using an NGK projected tip plug . Flat milled back to 70 cc giving me 11.0 to 1 down from the 11.6 with the dart heads the ports pored around 226 cc . Did my own 4 angle valve job with a Toledo EZ eccentric stone grinder

sounds like you have done well with those heads
nice job

[1980RS]

Its 72 camaro , leaf spring caltracs bars 3200lbs. Dan

Have to love that, 2nd gen F-body that gets the job done.

[6.50camaro]

Yes , Steve they've been rubbed on . stock 1.70 intake throat is now 1.83 with 2.055 valves the stock 1.299 ex throat is now 1.42 for a 1.60 valve. The guides have been trimmed down bowls have been opened up and reworked for good cylinder wall side port bias , pinch opened to 1.10 x 2.20 ,manifold opening 1.25 x 2.25 . chamber opened up valves unshrouded . A big thing I feel was the .460 reach plug was 2or 3 threads back in the spark plug hole. I relieved the chamber wall back till the end of the plug was flush with the chamber . also using an NGK projected tip plug . Flat milled back to 70 cc giving me 11.0 to 1 down from the 11.6 with the dart heads the ports pored around 226 cc . Did my own 4 angle valve job with a Toledo EZ eccentric stone grinder

sounds like you have done well with those heads
nice job

Thanks Steve . You do some nice work also. Dan

[steve cowan]

Yes , Steve they've been rubbed on . stock 1.70 intake throat is now 1.83 with 2.055 valves the stock 1.299 ex throat is now 1.42 for a 1.60 valve. The guides have been trimmed down bowls have been opened up and reworked for good cylinder wall side port bias , pinch opened to 1.10 x 2.20 ,manifold opening 1.25 x 2.25 . chamber opened up valves unshrouded . A big thing I feel was the .460 reach plug was 2or 3 threads back in the spark plug hole. I relieved the chamber wall back till the end of the plug was flush with the chamber . also using an NGK projected tip plug . Flat milled back to 70 cc giving me 11.0 to 1 down from the 11.6 with the dart heads the ports pored around 226 cc . Did my own 4 angle valve job with a Toledo EZ eccentric stone grinder

sounds like you have done well with those heads
nice job

Thanks Steve . You do some nice work also. Dan

The exhaust port can take so work to get up to scratch but the intake respond well, not having a small unworkable pinch definitely helps in my opinion.
Dan,
How do you find doing seats with stones,those powder metal seat rings can be tough

[6.50camaro]

Steve ,this was the first set of heads I did not counting a couple seats on a junk practice head I had . So I really don't have any experience on anything else. I just did thing very slowly ,not trying to make money just trying to learn thing for my self. Dan

[6.50camaro]

Steve, I did raise the exhaust port roof some till it match the top flange on my headers and work the short side some not wanting to hit water or ruin things .Mostly worked the bowls and guides ,focusing on a good bias to the cyl. wall side and getting a good throat percentage. Dan

[F-BIRD'88]

It would be interesting to now bolt on a out of the box as cast Sportsman II head (or similar as cast 200cc head)
and run it down the track. ET/MPH comparo.