255 Merucry Dyno Pull

[Randall]

Originally Posted by sidevalve8ba

I imagine that moves that '46 coupe along quite well! Enjoyed the video Randall. Thanks for sharing.

My friend was pleased with way it ran

[tubman]

Originally Posted by Randall

Glad you all enjoyed , that is the first flathead I have completely rebuilt,it has .080 pistons, stock heads, carb, intake stock size valves with 3 angle valve job and a Isky 817700 cam, springs ,adjustable lifters, I resized rods and replaced wrist pin bushings,
cam ,rod and main bearing, bought ol Rons book and asked Ronnie roadster some questions, thanks for the help!, its a little skidish seeing it come off motor stand and going wide open after warming it up on dyno thinking did I do everything right!

Interesting. According to what I can find on the internet (Isky's site), this cam has a lift of .325" and a duration of 240, while a stock Merc cam has a lift of .338" and the same duration (from the Tilden site). This cam seems to be a bit better than an 8BA cam, but less than a stock 8CM cam.

It is precisely the reason why I chose not to upgrade the cam in the Merc engine I installed in my car to a mild aftermarket cam. Perhaps "Pete" or some of the other gurus on this site can explain the error of my reasoning. I am also curious that the valves started to float at something above 4000 RPM, given the updated springs, etc. Perhaps the heavier adjustable lifters? My engine will rev higher than that without floating the valves; it doesn't make much more power, just more noise.

I do not mean to denigrate the O/P's build at all; he seems to have done a fine job on it. I just want to add to my knowledge of modifications to these engine. I also wonder what reworking the heads for optimum "quench" and a larger carb would do.

At the current rates, I can't afford dyno time.