I was pondering today, and thought I might just bypass the Ultimate TBI mod and just jump straight into the Holley unit, but I have a question. Would it be too big to run on a rather stock motor? I imagine that they are smog friendly as well.

But which one would be for our motors? All the ones I see are for trucks (4.3L and 5.7L).

 

670 will require a new manifold that will accept a 2" tbi unit. Either the Pro-Jection or a carb manifold with an adaptor. Im pretty sure tim said the edelbrock tbi manifold can be drilled out to 2" also.

At anyways with a stock engine you'll only really get gains from the manifold, but as your engine grows then the intake will be able to grow with it. It wont hurt anything for sure, but Id put the money twards exhaust or gears/posi first.

 

What exactly has to be drilled out?

 

wihtr the LT1 cam it woudl prolly be ok. i think it woudl be too much for a stock cam though, or at least a lot mroe than the motor needed.
the gasket it coems with is the adaptor. it necks from 2 inch down to the stock size.

later
tim

 

You need chip tuning with the Holley TBI. I stuck it on my engine after my stock injectors went bad. For the price it was worth it-$80 per injector or $260 for a better flowing TBI.
The Holley pulls great and further into the upper rpm, but it just runs too rich down low. I guess it really isn't to different than bumping up the pressure with the stock TBI's regulator.
All in all, there was a SOTP gain, but a loss in the wallet as gas and spark plugs get expensive. The AFPR is pretty nice. oh yeah, listen to Tim, he right on with everything he said. But if you are set on the Holley, they sell 'em with different size injectors. The 502-5 is for the 305 and comes with 57pph injectors. I believe the 502-4 comes with 50pph injectors, which would have been a better choice for my situation, but I did not know about. The one for the 350s are 65pph injectors, but you would run waaaaayy rich even with a cam.

 

$260??

At Summit the unit is $372......now even with the AFPR, would I still need to get a chip custom burned for me?

 

And what exactly was your "situation"?

 

EFI doesn't really care how big the throttle body is, that's mostly a carb issue. You could get a stock Lo3 to idle fine with a 670 unit so long as you had the correct injectors and some skills, a vac.AFPR would help the fuel issue.
The idea of not having enough TB is an issue I hope to resolve when I get the lockers finished I'll be able to datalog the WOT runs with 15 fps. When there is more than a 5kpa loss in MAP it's going to be an air issue.
Right now I've been steady with the 670 and not ever dropping more than 4kpa.
I do think that it's best to focus on other stuff and not until you're making ~230 hp should you even consider the larger unit.

 

You could also put the 305 GM injector pod on there and solve the rich problem and utilize the higher lb/hr holley injectors once your mods exceed your 305 injectors.

 

As I recall the 670 TBI comes in a 5.0 L flavor too.

http://www.jegs.com/cgi-bin/ncommerc...22&prmenbr=361

You should be able to get that unit to flow at about the same rate as the stock one, if not, grab an extra FPR to help it further, but I don't see why you can't get the flow down to a decent idle.

The CFM won't change much unless you remove the bottleneck that is your intake manifold. The bores should match the size of the TB else you're not changing it much.

 

Try Auto Zone. That is where I got mine. It may take a little longer for them to recieve it (mine was about 8 days), then say Summit, but for the price, it's a good trade off. $372 is a rip off.

refering to my post two above yours,
That was my ""situation"" Injectors went bad.

I had thought of that idea as well, and it is a good one. However, my stock injectors are bad, so I would have to purchase new ones which add up to $160. I figure I could use that $160 towards chip burning equipment instead. Thank you for the idea though.