MicroSquirt.com read only forum (Jan.15,2018)

I initially had a Rochester TBI and adapter that was removed from a 1990 7.4 powered GMC truck and set it up on my 1972 402 powered Chevy pickup. I derived from the calcs that these 2" bores can safely supply 300 horses. My engine is in the neighborhood of 330 and I am going to supply 20PSI to the 80# p/hr to the injectors by virtue of an adjustable FPR.

I had successfully run this engine for over a year with this setup when I had my MS1/V2.2 running the show but it just seemed to get more grunt with the Q'jet. I might not have had the fuel maps dialed in sufficiently at WOT but I am just wondering if this 2BBL TB is sufficient. I know it is in the neighborhood of 670 CFM but it seems to be on the edge of the allowable H.P. limit according to the Megamanual.

I could get some 90# p/hr injectors and try tuning with those but it is the air flow numbers that I am concerned with and I do not want any idle/low speed tuning issues. I know that this was on top of a 454 but it had a paltry 200 net ponies too.

I am getting anxious about diving in again but I want to make sure my components are up to the task at hand. I really don't want to go with a 4BBL TB and have to bother with the "staged" code for the secondary injector operation as this engine is pretty much stock with the exception of a mild towing cam.

Thanx in advance for the advice.
Bud

Well, since you already have it running it is pretty easy to tell if you need a bigger TB. Look at the MAP on a log showing WOT and high revs. If the MAP is not close to BARO (usually ~100) the engine is not getting all the air it could.

And then let us know what you find. I have one of those on the shelf maybe headed for a cad 500...