JDB840 wrote:Thanks for the info Eddie.
I might start a new thread about this so I'm not hijacking yours.
I friend of mine did the same engine combo as your 400 to a 512 with indy SR heads. The last track date of last year he ran a 9.90 in his 71 Challenger.
This is going to be a project of mine, hopefully it won't turn out to be a waste of time or money.
Could you ellaborate a little more on TBI air and fuel distribution? I would like to have the 6pak running the whole time, so I'm not sure if fuel dist would be a problem. I really wasn't considering a EFI, but that doesn't mean I won't move in that direction.
Hijack away my friend I'm just glad someone is discussing this with me. I'm not an expert but I am ASE cert. in F.I. repair and diagnostics. I was cert. in the early 90's but am going back to school to get updated on the new hybrid and 42 volt systems that all new cars/trucks will eventually go to. (They choose 42 volts because it 'usually takes 50 to kill someone, 42 was a good compromise between performance and lethality), a T.B. system is merely a electronic carburetor. All mechanical/electronic carbs will have some fuel distribution problems, much like electrical current, the air fuel mass will have droplets of fuel not completely atomised, some will drop out of suspension,(puddling on the intake floor), some will enter the intake port. With an injector, the fuel is sprayed directly at the back of a hot intake valve, and it becomes atomised and awaits in a perfect misted spray waiting for the valve to open,(thats why injected vehicles drive away clean on a cold day and carbs sputter and stall waiting for the intake heat to aid in combustion), so you can see why a sixpack of throttle bodies would be a lot of work for little gain. You would also have very little base info on tuning so a chassis dyno and a lot of man hours perfecting the drivaebility will be necessary, remember you will have to plot idle, load, vacum, temp. range, WOT,(Wide Open Throttle), Mass airflow or Speed density, Seqential, or Bank ect...it has been done but at the expense of much labor and testing. Another problem will be the throttle bodies themselves, 400 cfm is very small, G.M. might have made them as the 2 injector G.M. and Chrysler T.B. appear to have been made by the same suppliers in the 80's and early 90's (Holley was one supplier). With the injectors at the intake port,(port fuel injection), a large plenum single plane intake can be used very effectively. A port fuel injection with sixpack air only throttle bodies and 8 injectors sequentially driven is intriguing but would require a custom made intake and throttle bodies.