FIRST intake throttlebody conversion (completed with pics)
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion
well guys i am putting on the adapter and throttle body right now... ill take pics when the conversion is done.. ill post back in a few hours...
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion
ok guys.. here is just the plate on (sorry guys used camera phone)




Last edited by 88fastgta; Mar 12, 2012 at 01:21 PM.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion
and the conversion completed (again sorry guys crappy camera phone)




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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: FIRST intake throttlebody conversion (completed with pics)
I agree. That really came out good.
Re: FIRST intake throttlebody conversion (completed with pics)
Exactly what I was thinking- I would probably weld onto plenum. Do you think Ken would sell the manifold w/o the TB? I think he was insulted when I remarked the TB was 'brutish' looking- that wouldn't keep me from buying it.... but the linkage looks too cheezy. Now all you have to talk him into doing is making the oe fuel rails fit so I don't have to buy a new fpr.
Re: FIRST intake throttlebody conversion (completed with pics)
Any reason why the plate is so thick? Or is the new plenum that short- placing the TB more or less where it was with the old plenum?
How's it run?
How's it run?
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: FIRST intake throttlebody conversion (completed with pics)
"Now all you have to talk him into doing is making the oe fuel rails fit so I don't have to buy a new fpr."
I made the OE fuel rail system fit on my First intake manifold. However I did use SLP runners and the factory plenum. I had to have shorter cross over tubes made up. I also needed four adaptors for the bolt holes. You could add weld to the bolt hole area and drill and tap the four holes instead of using adaptors. I am not sure how much clearance there would be between the bottom of the First plenum and the factory fuel rail system for it to fit. One might have to mill off some of the First plenum bottom.
I made the OE fuel rail system fit on my First intake manifold. However I did use SLP runners and the factory plenum. I had to have shorter cross over tubes made up. I also needed four adaptors for the bolt holes. You could add weld to the bolt hole area and drill and tap the four holes instead of using adaptors. I am not sure how much clearance there would be between the bottom of the First plenum and the factory fuel rail system for it to fit. One might have to mill off some of the First plenum bottom.
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Joined: Dec 2008
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From: Mebane, N.C.
Car: Daily: Lincoln Town Car.
Engine: 355 SBC in the Fiero
Transmission: 5 speed F23 w/LSD
Re: FIRST intake throttlebody conversion (completed with pics)
Looks slick man! I don't know why you kept apologizing for your pictures, they looked sharp and clear to me (your camera phone is much better in quality than mine!)
Also big props to Ken at FIRST for going through the trouble of making a one-off part, that's some seriously dedicated customer service!
Also big props to Ken at FIRST for going through the trouble of making a one-off part, that's some seriously dedicated customer service!
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: FIRST intake throttlebody conversion (completed with pics)
Yes, in this thread. There are some pictures in the 4th post showing the OEM fuel rail. https://www.thirdgen.org/forums/tpi/...ifold-slp.html
I already had a highly modified factory plenum and SLP runners and did not want to start over again. So I made them fit the First intake manifold.
I already had a highly modified factory plenum and SLP runners and did not want to start over again. So I made them fit the First intake manifold.
Last edited by 1989GTATransAm; Mar 12, 2012 at 03:39 PM.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion (completed with pics)
drove it around guys and i have no more stuck throttle issues.... no power loss....no more high idle or anything.....all the problems i had before are gone and it idles like it used to back when i had the edelbrock/slp combo... i am sooooo happy..... its thick because the plate needs enough meat for the bolts to thread into the intake.... besides in person it doesnt look thick at all.. i like the look alot better.... here is a video of my car idiling with the adapter on....
http://www.youtube.com/watch?v=NUxzB...1&feature=plcp
http://www.youtube.com/watch?v=NUxzB...1&feature=plcp
Last edited by 88fastgta; Mar 12, 2012 at 06:02 PM.
Thread Starter
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion (completed with pics)
on a quick note the only mod i had to do was drill and tap a vaccum source for the pcv valve... the First manifold does not have a pcv manifold vac port so i just tapped into the side bracket where the egr would be on the FIRST to get my manfiold vac....
Joined: Feb 2001
Posts: 8,494
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From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
Re: FIRST intake throttlebody conversion (completed with pics)
As someone who has never like the appearance of the FIRST intake, I gotta say that looks a TON better than the LSx style TB. I really like it. ......if they'd only come up with a dizzy cover I might be convinced!!!!!
Re: FIRST intake throttlebody conversion (completed with pics)
Looks or not- if it performs as billed.....I pulled the trigger on the vortec style- EGR has been discontinued due to nondemand. Ken agreed that if I wasn't happy with the TB I would get a credit. I asked for gasket matching and install of PCV.
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: FIRST intake throttlebody conversion (completed with pics)
"if they'd only come up with a dizzy cover I might be convinced"
If the grooves lined up that could be done. Just a little milling involved and drilling and tapping for the screws.
If the grooves lined up that could be done. Just a little milling involved and drilling and tapping for the screws.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion (completed with pics)
It would be pretty easy to put a dizzy plate on here... just simply drill and tap bolts like stock and ur done... but I actually like the dizzy exposed..
Thread Starter
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iTrader: (9)
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion (completed with pics)
that would be 1989gtatransam that did that.... i think that was like 3 or 4 years ago when he did that....
edit.... i think this is what your looking for
https://www.thirdgen.org/forums/tpi/...ifold-slp.html
edit.... i think this is what your looking for
https://www.thirdgen.org/forums/tpi/...ifold-slp.html
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Joined: Dec 2008
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From: Mebane, N.C.
Car: Daily: Lincoln Town Car.
Engine: 355 SBC in the Fiero
Transmission: 5 speed F23 w/LSD
Re: FIRST intake throttlebody conversion (completed with pics)
When will you have it tuned and on the dyno! I've been itching to see that sheet!
(if you posted it already... I somehow missed it, and I apologize)
(if you posted it already... I somehow missed it, and I apologize)
Re: FIRST intake throttlebody conversion (completed with pics)
FYI, before I bought the FIRST I asked Ken if he would take back the TB if I didn't like it- he got it back and credited the amount of the TB, it'll be a wash as far as getting the adapter made, but at least I'm not stuck selling it.
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion (completed with pics)
how are you going to make an adapter.... ken made mine and all of my problems went away and i never had a single problem from it.... this is why i will never sell the intake because its truly one of a kind....
Re: FIRST intake throttlebody conversion (completed with pics)
In my mind- that TB had nothing going for it. New generation TB's have sealed bearings, etc real quality stuff, TPI TB's weren't great either but when rebuilt with bushings and bored/ported they are decent, mine flows 795cfm. I think Ken inhereted the package, I really don't know why the original engineer didn't make it compatible with as many oe parts as possible- easy to find, reliable, oe proven, cheap- I'll be making the adapter and reusing the fuel rails as the plumbing has no need of being changed for bling. Ken said he wouldn't be making any more of those adapters and suggested hp loss, but I'll take the loss over a better TB. That adapter should be an easy cnc- I've also opened up the throat on the plenum horizontally to ease the transition a little more. The adapter will be made out of 1 in stock and machined out- I also took the side plate off and welded the 90deg TB hole closed- the original throttle bracket will be positioned here as per stock.
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From: Charleston, SC
Car: '85 TA
Engine: 350 turbo
Transmission: T56
Axle/Gears: 3.70 posi 9bolt
Re: FIRST intake throttlebody conversion (completed with pics)
I got lucky and the guy I bought my used First intake from had an adapter made for it. I like the look of the stock TB much better and you don't have to mess with the sensor mounts. Everything else on the First is excellent.


Thread Starter
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iTrader: (9)
Joined: Mar 2007
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From: Raleigh, NC
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: FIRST intake throttlebody conversion (completed with pics)
yea everything on the first is excellent except for that throttlebody..... i guess me and you are the only ones that have adapted the stock type throttle body on these FIRST intakes... honestly i didnt notice any power loss either..... so i dont know what ken is talking about...
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Joined: Dec 2008
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From: Mebane, N.C.
Car: Daily: Lincoln Town Car.
Engine: 355 SBC in the Fiero
Transmission: 5 speed F23 w/LSD
Re: FIRST intake throttlebody conversion (completed with pics)
The possible power loss might be related to certain engine builds, or certain power levels and power bands.
So it might not affect 95% of the people out there (or be so minor that it would be attributed to a temperature change), but could noticeably impact other people.
So it might not affect 95% of the people out there (or be so minor that it would be attributed to a temperature change), but could noticeably impact other people.
Re: FIRST intake throttlebody conversion (completed with pics)
Hi,
Having MaxBore.com fab up a 1in spacer/adapter for my FIRST vortec intake. For my own reasons I'm continuing with the use of the original ported TB. This isn't a group buy- just a FYI if you want to add to the order, cost is $150 or if you know somebody cheaper....George will supply a 1 in alum plate with all bolt holes threaded and countersunk and will machine a basic +-2in slot for the GM TB- you will have to finish off with any tapers needed- since the FIRST is square and the GM TB is more 'oval' I see two tapers needed on the horizontal outboard sides TB side. I had George bore out a Toyota TB a few years ago and he did a good job. Ken at FIRST won't make these.
Having MaxBore.com fab up a 1in spacer/adapter for my FIRST vortec intake. For my own reasons I'm continuing with the use of the original ported TB. This isn't a group buy- just a FYI if you want to add to the order, cost is $150 or if you know somebody cheaper....George will supply a 1 in alum plate with all bolt holes threaded and countersunk and will machine a basic +-2in slot for the GM TB- you will have to finish off with any tapers needed- since the FIRST is square and the GM TB is more 'oval' I see two tapers needed on the horizontal outboard sides TB side. I had George bore out a Toyota TB a few years ago and he did a good job. Ken at FIRST won't make these.
Last edited by dfarr67; Jun 1, 2014 at 11:18 AM.
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Joined: Aug 2019
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From: Houston, TX
Car: 1992 Camaro
Engine: L98 TPI 350
Transmission: 700R4
Axle/Gears: 3:23
Re: FIRST intake throttlebody conversion (completed with pics)
I guess this thread is Dead !! lol I just got one of these intake and boy they are nice.
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From: Pasadena, TX
Car: 1991 RS
Engine: 5.0
Transmission: 700r4
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From: Canada
Car: '18 Chev Camaro SS 1LE
Engine: LT1 6.2L
Transmission: T56
Axle/Gears: 3.91
Re: FIRST intake throttlebody conversion (completed with pics)
Just to add to this thread for information:
Last edited by SbFormula; Apr 1, 2021 at 07:38 AM.
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From: Houston, TX
Car: 1992 Camaro
Engine: L98 TPI 350
Transmission: 700R4
Axle/Gears: 3:23
Re: FIRST intake throttlebody conversion (completed with pics)
The First Intake, is a nice piece, and the guy who makes them Ken, has always called be back every time I had to leave a message with him, he has spent a lot of time on the phone with me talking about all the little things that are involved with the changing this intake.
He did all of these this, even knowing.. I bought my intake system 2nd hand and not from him. Super Guy !
He did all of these this, even knowing.. I bought my intake system 2nd hand and not from him. Super Guy !
Last edited by Gen1; Apr 1, 2021 at 09:05 AM.
Joined: Jul 1999
Posts: 200
Likes: 3
From: Chesterland, Oh
Car: 92 Trans Am
Engine: 350 tpi
Transmission: 5 Speed
Axle/Gears: 3.42
Re: FIRST intake throttlebody conversion (completed with pics)
Very Nice. I been thinking about getting a 383 for my Trans Am. Do you know the hp/torque of your engine if it had a carb?
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Joined: Jun 2012
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From: Canada
Car: '18 Chev Camaro SS 1LE
Engine: LT1 6.2L
Transmission: T56
Axle/Gears: 3.91
Re: FIRST intake throttlebody conversion (completed with pics)
https://www.chevrolet.com/performanc...s/sp383-deluxe
Hotrod Magazine had it dynoed at a little more than that
https://www.hotrod.com/articles/test...t-performance/
With my FIRST intake, I'd say just a bit over 400HP with close to 500lb-ft peak. I haven't had it dynoed yet. Too much on the go. At some point I'll get it on the dyno to dial in the timing and AFR.
I pulled a 1/4 mile in 12.7sec @ 108mph for 3700lbs (gas & driver). 0-60mph in 4.5s, That's with drag radials on the street with 25lbs. On 94 Octane with 32* max SA and 12.7 ave AFR. 72DegF temp, Baro 103kpa and 50% humidity.
So I'd say 360RWHP, maybe 400-420HP at flywheel?
It's restricted though. Could improve on a lot of minor things like synthetic oil in tranny, rear end and engine. Better ignition system, full porting, but most importantly, 1 3/4 long tube headers with double pipes instead of 1 5/8" shorty with 2.5" single into 3" cat back.
Cheers!
Last edited by SbFormula; Apr 2, 2021 at 04:06 PM.
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Joined: Jun 2012
Posts: 1,367
Likes: 192
From: Canada
Car: '18 Chev Camaro SS 1LE
Engine: LT1 6.2L
Transmission: T56
Axle/Gears: 3.91
Re: FIRST intake throttlebody conversion (completed with pics)
The First Intake, is a nice piece, and the guy who makes them Ken, has always called be back every time I had to leave a message with him, he has spent a lot of time on the phone with me talking about all the little things that are involved with the changing this intake.
He did all of these this, even knowing.. I bought my intake system 2nd hand and not from him. Super Guy !
He did all of these this, even knowing.. I bought my intake system 2nd hand and not from him. Super Guy !
Re: FIRST intake throttlebody conversion (completed with pics)
Back when Precision Race Engines was selling crate engines they offered a carbed, dual plane, 10.5:1, 383 making 425HP @5800 and 440lb/ft @4500.
They sold a 383 FIRST combo with same compression and heads with an undisclosed cam that made 425HP @5500 and 500lb/ft @an undisclosed RPM. I suspect the cam was about the same and the peak torque was probably in the mid to high 3K range.
It doesn’t make quite as much power as SB’s SP383 engine, but should give an idea of what to expect to see on an engine around that power level.
They sold a 383 FIRST combo with same compression and heads with an undisclosed cam that made 425HP @5500 and 500lb/ft @an undisclosed RPM. I suspect the cam was about the same and the peak torque was probably in the mid to high 3K range.
It doesn’t make quite as much power as SB’s SP383 engine, but should give an idea of what to expect to see on an engine around that power level.
Joined: Jul 1999
Posts: 200
Likes: 3
From: Chesterland, Oh
Car: 92 Trans Am
Engine: 350 tpi
Transmission: 5 Speed
Axle/Gears: 3.42
Re: FIRST intake throttlebody conversion (completed with pics)
Thanks, that's exactly what I wanted to know. I'll lose about 20-25 hp but gain 50-60 tq. Not a bad trade-off. The only thing that concerns me from the video is that the peaks are at lower rpm than the carb version.
Last edited by JJ63; Apr 2, 2021 at 08:58 PM.
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