Speaking of Carb to TB Conversion ....

[Bamfster]

What would be the down side (s) to using say a Holley/Proform main body to convert to multiport efi. I know that TBs can be bought all day long, but why not a true DIY conversion .... am I missing something here?

http://www.mez.co.uk/ms2.html

[TheSilverBuick]

That's what I pretty much intend to do to a Q-jet, knock the boosters and upper butterfly's out and any other minor mod to make it work.

[Bamfster]

That link I posted shows a guy doing just that, but doesn't get into any detail. If I'm thinking correctly, it's just an air valve at that point....

Now what about CFM rating. Is this a case where there's no such thing as too big? I have a 700 and a 750 main body/throttle plate setup.

[1931s/x]

ive seen people that used a holley body for a throttle body. proform is a pretty nice body, but wouldnt you still want to remove the boosters? i guess that would increase the cfm too. would you have to fill the holes left and all the air bleed holes? would a 1:1 ratio be best for the primary and secondarys?

[TheSilverBuick]

An air valve is all a throttlebody is on multiport injection. CFM ratings can't go to big. However throttle body size and the openning ratio on the primaries and secondaries can effect the sensitivity of the throttle pedal. Too big and you can find that coming off idle is tricky as it'll quickly supply the engine with air (to which the ecm will supply the fuel). Either you get used to the sensitivity and adapt to drive it normally or you don't. I mean look at Jeff's small block with something like 4500cfm of throttle body. As for the ratio, it doesn't really matter, mine from Edelbrock opens the primaries almost all the way before the secondaries open, like a carb. Takes the off idle sensitivity out.

[Bamfster]

So in your opinion (keep in mind I'm running a 750 dp now) would that be about right for a TB? The other idea I'm kicking around would be a tunnel ram w/ 2 450ish carb bodies ......