[71 Ventura II]

Originally Posted by 462ta

running crower 60916 221/229 cam in a 406 with home ported 13's, never been able to get the power out of this combo--275rwhp 315 tq that it should, since that dyno i have home ported the heads added tri y headers (tried adv cam--lost power on same dyno), question is im only at 9/1 comp would bumping that up to high 9,s be worth the hassle and cost. im going to add 3.73 gears--have 3.23 now with 28in tire so it should feel better.

Real data from my car:
Both Ken Brewer and the Kauffmans proved that the #16 cam, in a 400, with unported d-port heads can produce 400+ HP!!! I will say Ken, the Kauffmans, and myself ran 1.65 rocker arms. With that said, if your heads don't have the elongated pushrod passages it will be perfectly acceptable to run the 1.5 rockers, just expect +- 8-15 less HP.

IIRC
Ken Brewer results 405 HP @5400 rpm and 470 ftlbs TQ @4000 rpm.

Kauffmans results 419 HP @5400 rpm and 470 ftlbs TQ @4000 rpm.

My results had to be in the same ballpark based on track testing. I ran my Ventura II with the 400, Hughes GM25 converter, and 3.70 gears with super TALL 29.5" bias slicks to easy 12.50-12.70 ET's pulling 105-107 MPH. Stock unported heads!

After porting my heads the same combo picked up big time running 12.20's @109 mph!!!

I am a big fan of the #60916 cam in the Pontiac 400! It will give you a strong "Muscle Car" exhaust note, pull hard to 5500-5800 rpm, and still pulls great vacuum of 15 lbs @1000 rpm idle.
My combo: Top down...
Holley #4779 750 DP
Edelbrock "Performer" w/1" adapter from the spreadbore to square bore carb.
1968 #16 heads w/Crower #68404 dual springs, Crane Energizer 1.65 roller rockers
Stock 1971 bottom end w/Milodon rod bolts, 60# oil pump, and cast pistons. With the rebuilder pistons I used the actual compression was 9.70-1.
Hooker "Competition" headers 1 5/8" 4 tube

TH350 w/Hughes GM25 converter and 3.70 gear. The GM25 converter is one of the most efficient converters I've tried. Converter contribution was 7.5% Not bad at all especially in the price range. The Continental will be tighter with a Converter contribution of 3-5% with a higher investment ratio.

My 3.70 gear running the 29.5" tire is the same effective gear as a 3.63. Inversely if your running a 3.42 gear with say a 28" tire you have the effective gear of a 3.54 or if your running a 27" tire your looking at effective 3.66 ratio. Gears are engineered assuming a 29" tire so for every inch lower you gain gear and every inch taller you lose gear. Bottom line your in the same operating range as my car... JD