When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm sure this has been discussed. However I'm curious as to the level of "plug and play" this unit is. What is the base requirement for install? I'm assuming at minimum I would need upgraded injectors. Other than that what can I expect? I'm not building this car for race. I just want a little more enjoyment when I drive it. I currently have a mostly stock 37k mile 305 Tuned Port car. It's been in the family since new in 86. I also already have the First TPI set up on hand. Any info on the bare minimum requirements to this unit will be appreciated. Thanks.
If your car is already TPI equipped you should only need the manifold components. If the heads and cam are stock you won't need to change your injectors. If you are still running the stock exhaust manifolds back, you likely won't see any gains.
If your car is already TPI equipped you should only need the manifold components. If the heads and cam are stock you won't need to change your injectors. If you are still running the stock exhaust manifolds back, you likely won't see any gains.
We did a little work to this car in the 90s. Mainly electronics. Factory TPI motor was left relatively stock. Just the old school chrome kit. It does have after market exhaust from headers back to muffler and shift kit in the 700r...I'm wanting to leave it tuned port for the aesthetic, nostalgic value. Obviously hp gains would be greatly appreciated. Just not sure I want to go with cam, lifters or any other internals on this car. I truly want to eliminate MAF because it's a pain to keep the relays behaving. Ha. Maybe the First set up was a little aggressive but here we are.
Might consider selling the first and investing in dynamic efi ebl flash 2.
Another good suggestion. According to their website I would have to obtain another ECM. I have an 86 IROC their suggested donors are 89-92 ecms. I'm sure not impossible to find though. Or maybe I'm reading it wrong. It would be a fraction of the First tpi cost though.
There’s a tbi ecm in the classifieds for $50 iirc then have them do the port mod and board on it if he doesn’t have any ecms in stock. Your 1227165 is worth a few hundred there hard to find working right now.
The FIRST needs a standalone fuel pressure regulator and you’ll need to run a new fuel feed and return line. Test fit it to see if you need to remove material at the “cut out” at the back of the intake to clear the rear china wall fitting before trying to bolt it down. Most fittings will require a little more area than what’s cast. Also the large cap HEI needs a little ground off the bottom of the distributor housing to sit all the way down. You can use your stock injectors on a lightly modified engine.
Just the adjustment in fuel pressure and base timing will allow it to run pretty good on the stock chip on a MAF system. I wouldn’t swap over to a speed density system unless the MAF sensor was bad and I had (or didn’t mind buying) the equipment to burn my own chips.
If you stick with a stock cam, the stock TPI with a little base and plenum porting would probably help about as much as just bolting on the FIRST. A lightly ported stock TPI base will flow more than the heads. The FIRST has large ports and runners better suited for modified 350 and larger engines. However, it would probably be worth the swap if you went with a larger cam and better heads, or plan to put a larger engine in it at some point.
The FIRST needs a standalone fuel pressure regulator and you’ll need to run a new fuel feed and return line. Test fit it to see if you need to remove material at the “cut out” at the back of the intake to clear the rear china wall fitting before trying to bolt it down. Most fittings will require a little more area than what’s cast. Also the large cap HEI needs a little ground off the bottom of the distributor housing to sit all the way down. You can use your stock injectors on a lightly modified engine.
Just the adjustment in fuel pressure and base timing will allow it to run pretty good on the stock chip on a MAF system. I wouldn’t swap over to a speed density system unless the MAF sensor was bad and I had (or didn’t mind buying) the equipment to burn my own chips.
If you stick with a stock cam, the stock TPI with a little base and plenum porting would probably help about as much as just bolting on the FIRST. A lightly ported stock TPI base will flow more than the heads. The FIRST has large ports and runners better suited for modified 350 and larger engines. However, it would probably be worth the swap if you went with a larger cam and better heads, or plan to put a larger engine in it at some point.
Great info. Thanks!!! I'm not opposed to shelving the First unit for now. The kit did come with fuel pressure regulator and plumbing. This car has a mid 90s Hypertech chip installed. It runs fine. Just a little lethargic as a mostly stock IROC typically was. We built a couple monster 3rd gen's back then. And by "we" I mean I was doing what my dad and brother told me needed done. This car was owned by my brother when I was in high school. Then shoved in his warehouse for years. I bought it few years ago. My son and I brought it out of storage at the end of 2020 when he was 14 to pass the time. Now that it's out I've really missed the power of some of those older builds. However, this is about as close to all original, numbers matching, low miles as it gets. I have all of the factory parts that have already been changed boxes up for whatever reason. And intend to keep everything else that I change. My kids can deal with those boxes when I'm gone. For now I want to enjoy the ride. It has been fun the last 3 summers running it again. I just don't want to get too extreme with this one so I can preserve even a little bit of the originality. I was never a fan of mass air flow. I was hoping to eliminate and keep the TPI. Maybe not my best option.
I'm sure this has been discussed.
Yes, lots of threads and videos
However I'm curious as to the level of "plug and play" this unit is.
Not plug and play at all
What is the base requirement for install?
You want to make sure you have the intake manifold that will fit your 305. The intake has to be modified IIRC. Check with Ken at https://firstfuelinjection.com/. You can also download the instructions from his site. That will help you with planning.
I'm assuming at minimum I would need upgraded injectors.
Not needed
Other than that what can I expect?
I did a "pilot project" on a stock LB9 ('91, 230hp version, speed density) with CAI, TPI foil, headers, single high flow catalytic convert, 3in cat back and custom tune (260-265 HP). I saw a tinny difference in power with the FIRST intake and my own retuning. It pushed the peak torque/HP up a bit. Here's a chart, all things being equal, I had to adjust VE tables at WOT to bring back WOT AFR to target (using AFR gauge). The engine was definitely breathing better but to what extent? Was it worth the money? This chart is not an exact science, just an idea of what the FIRST intake did to my set-up. About 3-4% peak VE gain, about 5-10hp if...
UPDATED: The FIRST TPI Intake was the 835cfm model with 1205 style port. It was installed as is on the 305 with no port match to the head. This was done because the 305 was to be swapped for a 383 in the future.
Some of the stuff I had to buy for fuel, coolant, wiring, etc... I did use flared fittings, a fake EGR valve (for inspection), a custom weathered connector for the IAC and other goodies.
Fuel lines mock-up
How ridiculously big the FIRST is for stock 305 heads
I'm sure this has been discussed.
Yes, lots of threads and videos
Thanks a bunch for the info. Coincidentally my interweb search brought me to your ride a couple times. Such a badass rig for sure!! I have a good bit to consider. Thanks again.
I'm sure this has been discussed.
Yes, lots of threads and videos
Thanks a bunch for the info. Coincidentally my interweb search brought me to your ride a couple times. Such a badass rig for sure!! I have a good bit to consider. Thanks again.
SB, I didn’t realize or had forgotten you installed a FIRST on a 305. Just so I’ll know for future posts, it does look like it helped the 305 based on the VE table. Was the TPI it replaced stock? If not, what had been done to it and to what extent?
Also, the original standard SBC FIRST’s base exits were cast (curving down at the top) to a 1204 (small, stock sized SBC port) intake gasket. I think Ken at FIRST was opening them up to the customer requested gasket size. The FIRST can be opened up to as much as a very large 1207 gasket.
It appears you bought the “Vortec” FIRST for a set of Fast Burn heads? If so, that’s why there’s such a big port mismatch on the stock 305 heads. Did you open up/ gasket match the stock 305 heads that Vortec FIRST?
it does look like it helped the 305 based on the VE table.
Yes it did and I could feel it at higher RPM.
Was the TPI it replaced stock?
Yes
Also, the original standard SBC FIRST’s base exits were cast (curving down at the top) to a 1204 (small, stock sized SBC port) intake gasket. I think Ken at FIRST was opening them up to the customer requested gasket size.
Yes Ken did some work to it. I wanted the 1205 port for the future 383. I had confirmed with Ken, the 835cfm model would be plenty for 383. People forget there are 2 models: 735cfm and 1050cfm. However, I needed the edge trimmed and modified center bolt holes to fit the 305. Here's info from an email he sent me some years ago:
"(...) the gasket supplied is for the intake which is a 1205 port, your heads have the stock 1204 port. We could make the base fit that port no problem but guys do not want the port that small on the intake side. As far as the center bolts go we make the base to fit that as well if requested. The FIRST tpi will bolt up to that head as long as we machine the center 4 bolt holes to accept them and add the counter sink. Also by the valve cover we machine the edge down to fit the ridge, believe me it will fit. If you want send the base back I can make all these modifications for you and show you it will bolt right up, no problems at all, (...)"
BTW, this is an example of the outstanding customer service Ken provides.
It appears you bought the “Vortec” FIRST for a set of Fast Burn heads? If so, that’s why there’s such a big port mismatch on the stock 305 heads. Did you open up/ gasket match the stock 305 heads that Vortec
Nope. The pilot project was to install everything to see how it would fit and work and learn how to tune with the old 305. Then, the 305 was to be swapped to the 383 and retuned. I would imagine, port matching would help flow. Again, lots of work, money and resources for a small gain on 305. Like you said: "The FIRST has large ports and runners better suited for modified 350 and larger engines"
I'm sure you know. '86 AT TPI were rated at 190hp!!! Not sure how much of a difference the FIRST TPI intake will make. I believe, but I'm sure someone here will correct me, you have the "peanut" cam. Not much breathing on that engine.
85/86 TPI 5.0L engine had a flat tappet cam. 85 TPI was a L69 5.0L H.O. long block with TPI induction and made 215 HP in a IROC-Z and 86 was a LG4 5.0L long block with TPI induction and made 195 HP in a IROC-Z. These engines made 5 HP less installed in a Trans Am. 86 had the weakest cam ever put in a TPI engine.
02-13-2024, 08:19 AM
