jimbob65

Dyno of LT1 conversion Lid and 85mm maf on my 236/245 Hyd roller cammed 401, thru 12 bolt, and locked auto. New numbers were with under drive pulley removed (went to SFI dampner), and heat range 9 plugs (for 200 shot) vs. heat range 4. New dyno numbers were way lean and I picked up 5tq and 6hp more than this graph thru the whole pull after tuning. 420.65TQ and 460.33HP SAE corrected now. My old numbers were 424.01TQ and 448.15HP SAE. So, I picked up 12 rwhp with this MOD, even after taking away a little with the pulley and plugs (I'm assuming that's were some of my torque went). Numbers Uncorrected were 439.54TQ and 481.00HP. Using this graph to show how my old combo was starving for air upstairs above 6K rpm...Nice gain with a upper rpm that looks more like a mechanical roller than my little HYD (for a 401 cube engine)...HP peak is now at 6425rpms instead of 6275rpms. Good Mod for me but I'm not sure less agressive combos would be worth it...time will tell.
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shoebox

When you want to make comparisons, you need to keep everything the same, except for what you are comparing. Also changing pulley, plugs, etc. throws the data off and makes the comparison unsubstantiated.

jimbob65

Exactly......Except mine made more power in the upper rpm, which is a gain. I'd call the loss of the underdrive pulley the reason for the lower torque number (sense that seems to be the only real gain with them). I can tell with my trusty Butt-O-Meter (take that with a grain of salt), that it does pull better in that upper rpms range on the street and dyno. Sense the gain is only in the upper rpms then I don't think many will gain anything from this MOD (on the dyno atleast). And, was the gain from the Air intake or the 85mm MAF? (that would be my biggest question........) There "may" be some trap speed gain due to a better cold air area to suck from but........Again who knows....Maybe someone will dyno a before and after on a stock combo (with stock MAF) and we will finally know.....