I just got some parts in that I ordered and had asked for an Edelbrock vortec intake to go along with the vortec heads that I also ordered.The intake that I got is part #3704 Performer TBI.Upon further review it looks as if this is a direct oem replacement and not a big upgrade.Will this intake even fit these heads?Would it be worth keeping? As I look at the Jegs website it lists a "vortec" Performer AND a "vortec performer RPM.It says they both are for 4 barrel carbs...how would this work for TBI?Like i said...I have the vortec heads and a new spring kit to be able to run the Comp 276HR-14, Comp Controlled, Hyd Roller, 276/290-220/230-.510/.510-114.I'm also getting headers and a good exhaust to go with it.I had planned on keeping my ultimate modded tbi so I really don't know which intake is right.Am I on the right track here?

92 305 rs tbi

 

ok...so I'm a little slow..lol...I've come to conclusion the tbi performer won't work with the vortec heads after physically mating them together.I guess I need at least the Performer RPM Vortec.My next question if anyone knows is...Will I be able to close my stock hood using the vortec intake with a tbi adapter plate?Where could I get one?Thanks

92 rs 350 tbi

 

I doubt it. I have a '71 Camaro with the Vortec heads and a Performer intake, and I have to use a 1.5" air cleaner to close the hood.

The RPM is gonna be a little taller. Not saying it can't be done, but it'll be tight.

 

Is that going on a 305? I think that cam will be way to big. I run it in my 383, an it pulls to the max ecm rpm of 6,400rpm, that is with a 2" 2bbl tbi. Also, I may be wrong, but you may need to do more work than just springs to make those heads capable of handling that lift.

This is just my suggestion, but if you plan on keeping the 305 and using the heads and cam:
Have the heads milled to 58cc to keep compression
Look into a single plane manifold
Consider a holley 670tbi with 65pph injectors

I run the performer rpm airgap, and like it. It did wonders over the performer I had on there, and I consider the performer rpm intakes to be the best dual planes for the vortecs. But I really think single plane is the way to go for high rpm engines. Also, with the adapter plate, my stock hood would not clear.

 

on milling the heads .....

i don't think we've ever gotten a definitive answer on how much you have to mill a set of vortecs to get from 64cc to 58cc. has anyone actually done this and ccd the heads afterwards? when this comes up, people will often state their opinion, or the opinion of a machinist they've talked to, but i don't think i've seen anyone saying they've actually done it.

also, when you mill vortecs to 58 ccs, won't that greate valvetrain geometry issues?

 

there is a Vortec TBI manifold, by the way, but it isn't an Edelbrock, it's made by GM. goes for $309.99. probably better and cheaper with the RPM, but just thought I'd throw that out there....

 

I installed the Vortec's on mine without any milling....

A big increase in power. I doubt that you could tell any diff with a little more compression after milling.

My 2cents.

 

Milling the heads to 58cc keeps the compression at 9.3:1 given you use a stock thickness head gasket. I'm not too sure what leaving them at 64cc lowers the compression to, but using a thinner head gasket will bring the compression back up a little.
Milling the heads should not create an issue.

 

I'm very interested in your setup since its very similar to mine.Are you running the stock hood?What kind of adapter plate did you use for your TBi?I was thinking of this one,http://www.painlessperformance.com/catalogframe.htm.Its torward the bottom of the page.I was hoping it was thin enough to allow the use of the stock hood.What kind of tuning issues did you run into?Did you buy a chip of have it burned?It would be great to have a heads up on some of the pitfalls.Does anyone else think the Comp 276HR-14 is way too much for this setup.I bought it on recommendation of a local speed shop who said it has alot of lope(which I want) but could still work with the stock converter.They said I might have to have some vacuum assistance but that wouldn't be a major hurdle.Any thoughts on this?

92 305 rs tbi

 

bloyurdoorsoff

I made an adapter plate on a mill and it on top of the RPM intake with a taller LO5 breather just does miss the top of the hood with no liner on it.

I burn my own chips. I am not one to give advice on that as I'm still a beginner in tuning but the chip programming and burning part is eazy.

This is just my advice but I would go with a mild cam to begin with.

 

bloyurdoorsoff

I made an adapter plate on a mill and it on top of the RPM intake with a taller LO5 breather just does miss the top of the hood with no liner on it.

I burn my own chips and it will some tuning. I am not one to give advice on that as I'm still a beginner in tuning but the chip programming and burning part is eazy.

This is just my advice but I would go with a mild cam to begin with.

 

howell engineering has one that is 1/2 inch thick....

 

It is tight but can be done. My buddy runs the vortecs and a performer vorec intake with an adapter plate. His open elemet is snug under the hood but it fits.

I am pretty sure it is .020". I may be off a bit but that is what my buddy did that I just metnioned in the above quote. he combined that with a thinner head gasket and everything works great.

This is correct but it doesn't seem like it is worth it since a better intake and a adapeter is far superior to it.

 

what is the issue with GM vortec intake? is it a truck application?

 

It's very expensive.

 

Well they are made to fit anything that has vortec style heads. It was origoanlly desinged for those truck guys who wanted to keepo their TBI set-up but benifit from the better and new vortec style heads. Like all GM perofrmace intakes, they are better than stock but not as good as the rest of the aftermarket.

 

as far as the intake goes I am running Edelbrock Performer Carb manifold with the holley TBI adaptor plate with a 2.75 open element. I ripped out all of that liner stuff too. Its a tight fight but it closes.

Hope this might help

 

I pulled my heads (heavily home ported 416s) to have some guide work done and at the same time I had them milled and went from 8.8:1 cr to about 10.

The difference in mid range torque was insane and dropped my et by a little over a tenth on average, not adjusting for traction problems... maybe almost 2 tenths on a 13.6 car thats alot more of a difference than a tenth in a 15s car

Ill bet if you milled your heads youd really like the gain. Compression is great.

 

Thanks for the info.....

The Vortec's are coming off the 305 to go on a 350 I'm building. I will be replacing the Vortec's with a set of 081's that I've ported and just have to mill down the guides, install new springs and seals and maybe install new valves. The 305 still runs strong but I'm just going to use it until the 350's ready and then the 305 will get freshened up and installed in my S10.

Later.....

Darrell