69 corvette

[steve rossi]

Would appreciate any help or ideas as I am new to this site. I currently own a 69- 427 corvette-the 390hp version to be exact.It has edelbrock performer rpm oval port aluminum heads, comp cam-230 duration-520 lift., torker 2 intake, 750 speed demon carb, headers, msd ignition, and 373 gears.
The car runs phenomenal. Hits over 50 in first, and gets there quickly.
Up to 120mph, it's a monster. After that, it seems to get flat at about 125mph, and is at 5500 rpm. The rev limiter is set at 6000 rpm.My question is this. Are there any other factors other than the gear ratio that might be effecting my top end speed? Sorry for the length.

 

[Jack]

The rev limiter is set at 6000 rpm.My question is this. Are there any other factors other than the gear ratio that might be effecting my top end speed?

Steve, Welcome aboard CAC! Flat at 5500. Assuming you have MSD box with plug-in chip or plug-in variable rpm controller ... have you tried unplugging chip? ... did that make any difference?

 

[steve rossi]

I'm not a mechanic, but even though Randy has rev limiter set at 6000, it seems to be not gaining much above 5500 which is where the stock original tach shows the redline. Of course if I over rev, it will shut down which is
what it's supposed to do.I guess I could push it a little more, but the engine sounds like it's not gaining much after 5500. Maybe I'm expecting too much with a 3:73 gear ratio. It runs perfect. Randy told me if I want more top end speed would have to go with something like a 3:23.But I like the explosive
off the line speed with the 3:73