I plugged in the following data for desktop dyno (basically my ride with a comp xe256 cam) it showed a peak of 267 hp at 4500 rpm... seems a bit high.

heads: unported 416 with stock valves (data entered from thread https://www.thirdgen.org/forums/tech...416+heads+flow assuming similar flow data for the 081 heads)

9.5 compression ratio (I thought the 85 LG4 was lower, but that's what tech data on this site says)

750CFM 4bbl induction (qjet, reference: http://home.earthlink.net/~quadrajets/quadrajet_airflow_ratings.htm and didn't make a difference going as low as 600 cfm

dual plane std flow intake manifold (i thought the LG4 intakes were notoriously restrictive but desktop dyno doesn't really give you many options here)

small-tube headers with mufflers

xe256h-10 cam. also trying an xe-262h-10 showed 271 peak hp at 4500 rpm

anyone with a similar build have real world numbers to back that up?

 

what desktop dyno program version are you using? i got this old 2003 version and everything i do so far is somewhat on the higher side. I tend to model it with small tube headers/mufflers and less induction flow to make power seem more accurate.

267 crank hp doesnt seem that bad tho. closer to 215-220 ish whp i'd say which is doing well for a 305 but i've seen some bolt on 305's dyno 190-210whp so one with a cam should do that. Its safe to say its probly in the 250-260 crank hp range as DD tends to go alittle high

 

DD ASSumes that everything is tuned perfectly.

 

Yeah, i'm using DD2003. Thanks for the replies, I'm guessing with backyard tuning I'd probably be ten or fifteen horsepower lower?