What are the flow numbers for a stock SDPC vortec base / SLP runners and what are the flow numbers for the FIRST Vortec complete intake setup?

Also, what CFM is the FIRST throttle body rated at?

Would it be possible to weld an adapter plate to the FIRST plenum to accept a factory style (2 blade) throttle body? Would it be wide enough to do so?

Any info would be cool, I'm thinking of switching to the FIRST setup.....

 

Don flowed a SDPC Vortec base and it was the worst performing aftermarket intake manifold he has tested. Flow numbers ranged from the high 220's to the 230's per port. Add the runners and it will flow even less.

My out of the box First flowed 301cfm with probably the most restricted port. Add the runners and the flow will drop some. I just don't know how much the drop would be.

One of the local club members had a complete First unit and I looked into the possibility of adapting a factory style throttle body to it. It could be done with an adaptor plate as you indicated.

 

Cool, now the next question is: Is the FIRST plenum wide enough to accept an adapter plate for a factory style 58mm throttle body and is it wide enough in the back to machine a notch (cut, weld, drill/tap 3 holes) to accept a factory TPI plenum distributor cover?

I will be trying to make it look as factory as possible...

 

It looks like the FIRST plenum is quite a bit more narrow than the factory plenum...

Anyone have measurements?

 

You could always trim the distributor cover if it was narrower. You could also use the aluminum one from the Corvette and trim it. I don't think it would be to hard to camouflage the First unit to look like a factory setup.

 

If the SDPC intake is so bad...Is there another alternative to buy, to use TPI & a stock TB on Vortec heads?

 

You could consider the edelbrock, PN 3817, dont really know how it flows though...

 

The edelbrock and SDPC ARE the same intake.......

 

There is a lot of potential in the Vortec TPI intake but it takes porting to open them up and release the potential. Out of the box they are not that great. Out of the box the First Intake is the best we have seen by far.

 

835cfm but they will custom make bigger for you if you want bigger, just email them and talk to Ken

 

first injections 4.3 inches where the distributor cover bolts on

stock unit 4.75 inches where the distributor cover bolts on.

 

I have a spare stock TPI plenum to hack up for the throttle body adapter plate and since the difference in width is only about a 1/2 inch, I could trim an aluminum vette TPI rear distributor cover about a 1/4 inch on each side and center it...... Then smooth down the welds on the FIRST plenum after modifications and then polish it and the runners......

It's getting interesting!

Next question is, what does the FIRST fuel rails have a fuel pressure regulator inline like the factory rails or do you have to rig up an external regulator inline with some braided line?

Is is possible to use the factory TPI fuel rails / regulator?

 

No you cant use the factory regulator, you'll need something along the line of one of these

http://store.summitracing.com/partde...5&autoview=sku

here is the FIRST web site
http://www.firstfuelinjection.com/
----------
In this thread, there is an comparison of the FIRST to a ported SLP set-up and the HSR

https://www.thirdgen.org/forums/alte...rformance.html

 

Also a group purchase is currently running in the group purchase forum.


https://www.thirdgen.org/forums/grou...ml#post3964043

 

I was able to use the factory rails and fuel pressure regulator with modifications but I was not using the First plenum. I believe the above poster might very well be correct. They just won't bolt on that is for sure.

 

Then would it be a better option to just trim a factory plenum and modify it to accept the FIRST runners?

 

no, it would be a heck of alot of work to do that, if it was even possible

 

Well, I dont know what would be more work?

It would still be alot of work to weld on the factory style throttle body adapter plate and then section the rear to accept a modified rear plenum distributor cover.

If I just shaved the sides of the factory plenum, welded a plate to each side with the runner holes cut into them, then just drill/tap for the FIRST runners to bolt up, it may be less work than modifying the FIRST plenum....??

The whole idea is to use the FIRST manifold and runners, but also utilize my Holley twin 58mm throttle body and have it all look as factory styled as possible.

What do ya think?

 

Why not a 3/8" aluminum adaptor plate to mount the throttle body to. A lot easier to do than the runner thing.

 

Well, it would still be a chunk of work on the rear area of the FIRST plenum for the distrib cover....