I'd have a Chip burned for my application, not sure if i want to keep TBI or not, I have Pro comp heads, with 2.02/1.6 valves with a 3angle Valve job 195cc intake runners, 64cc CCV, I'm looking at a 650 CFM Carb or TB unit the Cam is a 168H Comp Cam, and it will work with the Computer after tuning. Not sure if TBI is the answer for making the most available TQ/HP. What are you thoughts?

Do a search and see how many people will tell you to stay with the FI. Wether its TBI or not it will start better/easier/get better mileage and run great, without a loss of power. I would assume that you have a compXe268h cam right?? You will need to get into chip tuning for yourself to get the most out of the combo. You wont be happy with an aftermarket chip etc. You will have no problems powering that combo with Tbi. Just ask Fast355 or Dimented or many others here about there great results with the simple TBI FI setup. Im sure someone else will comment. Just my 2cs

I Want to keep the EFI, Keeping TBI would be cheaper for me, I Tried reading up on all the Burning your own chips, and I keep getting Side tracked and forget things half way through.. I noticed In the summit Racing Catalog, theres a Company that asks alot of in depth Questions and they Can burn a chip for $400.00. Which is quite alot. I dont think the Stock TBI unit will flow nearly enough CFM for my Cam/heads.

I might get a 4bbl TBI with the computer and stuff, I dont know for sure yet. I'll be pondering alot tonite, and rereading the Chip burning threads. I do have a Caprice ECM, with a Caprice Cop car Chip right now... Runs a bit rich...

Here is my

Stock TBI with ultimate TBI mods and a 30 psi regulator spring will support 320 HP. Putting a stock TPI pump on your sending unit in your tank will support 400 hp running at 30 psi.

This setup will run anything you can throw at it and tunes very easily. No real extra hardware to buy if you have a laptop. No prom burner, prom eraser, chips, or chip adapters, or aldl cable needed.
http://dynamicefi.com/

WOW! I am really Considering that EBL Flash system. Do you have it?

I have never used anything like tuner pro? I dont really know how to set Parameters for Fuel and air, I suppose thats where the O2 sensor comes in?.?. They make it seem Very easy to use, but of course, anyone selling something makes it seem that way.

I do have a TPI Pump in place already in my camaro. Stock 350 Injectors, not sure what they are rated at for lbs... I have my Regulator Maxed out. Probably should get the 30 psi regulator.

I do have a Labtop and i can solder, but nevel done any computer soldering.

Thanks alot fast355!

Brian Harris (Harris Performance) and I have been working with a guy who has the Comp Cams 8-304-8 and Pro Comp Heads (2.02/1.60). He is running a TPI pump, 90lb flow matched injectors @21psi (injectors are matched at 980cc/min @14.7psi), 50mm TBI and I believe a performance GM TBI intake.

His results from the dyno last week was around 355hp at the flywheel. The heads in this case are limiting anymore.

My project this spring is:

8-304-8 Comp Cam
1.6 Magnum Roller Rockers
AFR Eliminator Heads
Edelbrock Performer TBI bored to 50mm
454 TBI
90lb flow matched injectors
Aeromotive 13301
High flow fuel pump (already installed
9bolt 3.27
Obviously, custom chip tuning, etc

I am hoping to get 385hp or more at the flywheel.

I will be doing a few other mods as well. I already have 3" stainless Magnaflow high flow cat, 3" Magnaflow cat back, Hedman Hedders with y-pipe (custom will be done when mods are done), UMI goodies all over the place, etc etc etc!!!! CANT WAIT.

Yes, the 2.02/1.6 Valves are stupid to have with a cam that has less than .600 Lift, But had my valves unshrouded (little bit of grinding) and a 3 angle valve job done. But yea your right about that.

My transmission is rated at 350hp. 350hp would be a HUGE improvent over the 170hp-200hp i have now!!

Absolutely!!! Huge improvement!

DC, that sounds like a nice buildup, the only thing that I'm a little worried about is the Edelbrock TBI manifold. The dyno curves they have on the their website where they did a buildup using that manifold are pretty discouraging, for all the parts they used (cam, heads, manifold) the HP gain was pathetic.

I think that manifold is targeting pretty low RPM usage, and I'm afraid the ports are too small for what you want to do, but I haven't seen one in person, so if you have experience with them, please fill me in.

I do have one of the Holley TBI manifolds that I bought for a build up that is unfortunately on hold right now. The Holley manifold looks pretty good, the port size compares favorably with an Edelbrock Performer manifold that worked real well for me on a carb'ed engine. The way its designed it looks like it also would be effective to use the "cut down the center divider" trick to get a little more high rpm flow if needed.

The only rub I see on the Holley manifold is that the EGR flange is at a dumb angle requiring you to probably have to use an adapter if you need to have EGR.

Paul T.

Hey Paul!

That is my only concern as well. I have seen a few with a similar setup and manifold make around 350hp. I hoped boring it out to 50mm would help on the top end, but not sure. I have looked at several other intakes, but the clearance issue is a big factor under the hood of my firebird. If I go with a nice ram air hood then i have a few extra inches to play around with and can go with a nice carb intake and adapt my 454 TBI to it.

Well if hood clearance is an issue then the Holley manifold might not be an option, the mounting flange does appear to be raised some.

Its possible the Edelbrock manifold is ok, but boy those dyno curves on their site look discouraging and I haven't heard any one ever say many encouraging things about that manifold, and I don't think you'll be able to make 385HP at the flywheel with it. I've been curious to take a look at one to compare against the Performer and Holly manifold I already have but I haven't come across one yet.

One thing that could possibly be done to help the high RPM flow is the center divider cut down I mentioned in the last post. This doesn't look like it can be done to a stock TBI manifold but would work on the Holley and may work on the Edelbrock.

But if you don't already have the Edelbrock TBI manifold, with the rest of your combo I think I'd be looking to see if you could make something like a Performer RPM and an adapter work out. It might be possible to machine the manifold mounting surface down some to allow more clearance room for an adapter plate, let me know if you need help working that out, I have a cnc mill in my shop and could probably fab something up for you, as long as your not in a big hurry, I'd need to steal some time to do it.

Paul T.

The Edelbrock TBI performer has 42mm bores compared to stock which is 44mm. I have opened them up to 50mm which will allow a bunch more airflow than it's original design.

The adapter you see pictured is 1/2" thick and the TBI 3704 intake is .25" taller than stock intakes.

I used modeling clay on top of my air cleaner to determine how much space i had available and I can go a total of 1.5" and still have a bit of room for airflow as i have the K&N filter and top.

Geez, that powder coated TBI unit looks nice.

Having that 1/2" adapter gives you some options, after you get it running if your logs show too much pressure drop on the intake system I'd try opening up the center of your adapter to allow cross flow between the bores, this is similar to the divider cut down I was talking about.

Another option would be to port the intake runners on the head surface side of the manifold to get some more flow.

How well do the intake runners match up to the ports in the head?

Paul T.

The adapter is being used because the TBI that I am using has the larger base footprint for the IAC valve passages. This now seals the TBI. So the adapter is a must. I am going to open up the adapter completely between the bores and "try" to mill down between them on the intake as well. Very similar to CFM-Tech's Powerplate.

I thought about matching the intake to the heads. I think if I do the above and then match the heads/intake I should be able to get into the low-mid 6000 range. The CompCam has a range to 5500 rpm so i may swap that out. The Edelbrock is the same 5500 rpm.

The TBI and injector pod are powder coated gloss black. The intake is powder coated with the "mirror-finish". Two-step process with a powder coat clear as the final step!

Sounds like a good plan DC, please report back how it goes.

Paul T.

It will be done this spring. Before i do that I am doing 3 dyno pulls. I want before and after results.

Currently, I have a stock 350 with all ultimate TBI mods, open element, no smog, hedman headers, y-pipe, 3" stainless high flow Magnaflow cat and 3" stainless Magnaflow cat back, 700r4, 3.27 9bolt, etc etc etc.

not sure if this helps. but i was told by cfm technologies that they have a tbi and chip set up that will run the ZZ350 gm crate engine just fine. this is the engine i was going with. prolly still am. but i am going to go carb in the end. especially since i have a brand new procomp hei and performer intake for less than 100.00 bucks.

You are wrong there. I run 2.05/1.65" valves in my Vortecs and have flow improvements, EVERYWHERE.

I did alot of flow bench testing at school (NTI mooresville, NC) and the 2.02/1.60 Valves on a regular SBC head (nothing fancy/not vortec) wouldnt flow as much as you'd think until you reached the .600 lift and then flow rates Increased alot.. however i didnt get to flow bench any 2.05/1.65 valve equipped heads. so who knows..

Also if the heads are not properly setup in the intake/exhaust bowls and you just slap 2.02/1.60s in them, you won't see anything. But get everything sized properly through the intake port and bowl, clean up the guide, etc, and you will be amazed what can come in. I am at nearly 265 CFM @ .500" on the intake of my Vortecs, should I mention it still only has less than 180cc intake ports!

I had a 355 with TBI injection in a silverado with a 5 speed man and 3:42 gears. They can be built to be very fast. I had the edelbrock TBI manifold on it, but the bores were only as big as the stock throttle body. There is a guy on Ebay who makes custom throttle bodies for TBI. I sent him a core from a 454 throttle body. He sent me back a completely refurbished one with new butterflies that flowed about 850cfm. I also bought some 65lb venom injectors and rebuilt the injector pod and added an adjustable fuel pressure regulator. I am a machinist in the Air Force so I took the edelbrock manifold into work one evening and bored it to match the throttle body. It made a BIG difference. The engine was rebuilt with the works and the compression was bumped up which seems to help out alot as well with these motors. The throttle body modification seemed to be the last key to turn to open it up with all the work that had been done to the rest of the motor. If you want the link, I think I still have the guy's ebay profile. He does very good work and had the new throttle body to me within a week. You can buy plug in adaptors for the IAC and TPS since if i recall the plugs were different for the small block throttle body. Anyway, to sum it up, I became a believer in TBI after the built up. Wish I still had the truck, it was a great Hemi killer

If hood clearance is an issue consider the low profile Weiand X-cellerator(single plane) with a TBI adapter. $140 plus adapter?