HP Estimate without dyno?

1980Esprit

1980Esprit

New member
Joined
Jan 8, 2013
Messages
154
Reaction score
0
Points
0
Age
28
Location
Virden, Manitoba, Canada
Hello everyone, I was wondering if anyone could help me with guessing how much power my engine will produce. It will be about a year before we can get an unbuilt motor to the dyno so I am eager to see what it would be.

I have a 1972 pontiac 400 block from a Pontiac Laurentian (Canadian only model I think but is similar to Bonneville)

I think it was either 180 or 220 hp stock. It HAD 7K3 heads (96CC) -- 4 bbl

It is now .030 on pistons, 0.10 crank on both mains and con rods. Compression will be 10.2:1 (Stock compression was right around 7.5:1), comp cams 262 XE hydraulic flat tappet, reworked Q-Jet, performer rpm intake, KB hypereutectic pistons, edelbrock rpm heads (72cc), Other than that it is mostly stock, will be getting full roller rockers when get more money for project. Hooker super comp headers.
 
have you tried downloading the competiiton cams software, you plug in all the factors about the engine select the cam and it gives you estimated HP. Using the older gross HP standard you are duplicating a 70 or older 400 which had about 350 HP gross stock, and maybe 275 net.
 
sorry, I got it. It shows 439 HP at 5000, and 510 lbs of torque at 2500!!
______________________________
 
Last edited:
wow, that sounds awfully high
 
You have to be signed on to facebook with your profile I assume, it doesnt work. I'm not doubting the results but something doesnt sound right with the parameters you are choicing when using the software. Unfortunately I have it on my home computer and cannt check it now. I'll try downloading it and see if I can input the engine specs from your email.
 
I just tried it and got about the same numbers 439 HP and 500 torque, still question whether those are valid numbers. Seems like if you increase the engine size to a 455 the numbers actually go down.
______________________________
 
I had entered the 455 with the 262H cam as I have in my 400, it will show at 450hp @ 5000, 572 ft lbs @ 2500. It seems pretty nuts. I know that the pontiac/olds/buick, especially the olds had some pretty serious torque numbers with the bigger v8`s but it just seems off because it is unusual.

I guess the numbers seem alright from the money that is put into it. I have around $2300 into it and have yet to put around $3800 yet into it.
 
You may want to consider the competition cams roller tipped rockers, not the full rollers, they give you somewhat more lift and will do fine with the rev limit of the cam.
 
Dont believe you can safely rev the engine to the point where there is an advantage to roller rockers.
______________________________
 
You must log in or register to reply here.

Share this page

Back
Top