89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
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Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
The Walker Exhaust part numbers are:
Outlet Flange with machined ring: 41688 (rockauto $38, but check other places, amazon?)
Machined outlet flange: 35747 (rockauto $40)
Vband: 35746 (rockauto $17)
You can view the dimensions in the Walker Exhaust HD accessories catalog online pdf file
I didn't know HF had an AC/DC TIG box. Do you have the model number for it? All I could find is the DC machine. The Miller MIG would do a nice job welding that up cleanly too.
Outlet Flange with machined ring: 41688 (rockauto $38, but check other places, amazon?)
Machined outlet flange: 35747 (rockauto $40)
Vband: 35746 (rockauto $17)
You can view the dimensions in the Walker Exhaust HD accessories catalog online pdf file
I didn't know HF had an AC/DC TIG box. Do you have the model number for it? All I could find is the DC machine. The Miller MIG would do a nice job welding that up cleanly too.
Last edited by junkcltr; May 19, 2011 at 11:18 PM.
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
I love nos
The only thing i love more than nos, Is a roots blower
The only thing i love more than nos, Is a roots blower
Last edited by jdmidwest; May 19, 2011 at 11:21 PM. Reason: just cause
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
The Walker Exhaust part numbers are:
Outlet Flange with machined ring: 41688 (rockauto $38, but check other places, amazon?)
Machined outlet flange: 35747 (rockauto $40)
Vband: 35746 (rockauto $17)
You can view the dimensions in the Walker Exhaust HD accessories catalog online pdf file
I didn't know HF had an AC/DC TIG box. Do you have the model number for it? All I could find is the DC machine. The Miller MIG would do a nice job welding that up cleanly too.
Outlet Flange with machined ring: 41688 (rockauto $38, but check other places, amazon?)
Machined outlet flange: 35747 (rockauto $40)
Vband: 35746 (rockauto $17)
You can view the dimensions in the Walker Exhaust HD accessories catalog online pdf file
I didn't know HF had an AC/DC TIG box. Do you have the model number for it? All I could find is the DC machine. The Miller MIG would do a nice job welding that up cleanly too.
vs racing might have the entire assembly for 40 bucks, i have to send them a picture tommrow and measure the degree of the vband assembly
here a link
http://www.harborfreight.com/welding...out-98233.html
i got mine from a place on ebay for much cheaper ,granted its a 240v machine but i have access to the electrical box at my apt so its nothing for me to wire in a temp 240 line

Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
I'm going to hit up a couple semi JYs to try and find some bends and the vbands. Dunno if you have something by you like that. Besides that, RPS should have something that fits that.
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Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
If VS Racing can sell the entire setup for $40 then that is a deal. Usually for the SS clamp and flange from someone that machines it themselves ends up around $100.
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From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
here a link
http://www.harborfreight.com/welding...out-98233.html
i got mine from a place on ebay for much cheaper ,granted its a 240v machine but i have access to the electrical box at my apt so its nothing for me to wire in a temp 240 line

http://www.harborfreight.com/welding...out-98233.html
i got mine from a place on ebay for much cheaper ,granted its a 240v machine but i have access to the electrical box at my apt so its nothing for me to wire in a temp 240 line


It does arc/dc not ac/dc. It is a straight DC machine. I bet it works quite well. I have used a china CUT50D plasma cutter a fair amount and it has cut up to 1" thick mild steel without grenading.
You could make an extension cord from an electric clothes dryer plug if one is available. Note to self->never rent to a car guy, ha ha.
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
race part solutions has a 5" mild steel flange with stainless steel clamp assembly for 62 bucks
http://www.racepartsolutions.com/products.asp?cat=106
http://www.racepartsolutions.com/products.asp?cat=106
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
My buddy has one of these, the only down side is the scratch start. He did some stuff with it though and overall it was worth the price he said. Personally I'm a MIG fan but hey a good MIG is usually cheaper than a good TIG and I'm here for the performance.
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From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
race part solutions has a 5" mild steel flange with stainless steel clamp assembly for 62 bucks
http://www.racepartsolutions.com/products.asp?cat=106
http://www.racepartsolutions.com/products.asp?cat=106
Also, something doesn't seem right with the Walker catalog. The correct 41655 flange calls out the 35746 vband, but from memory I used the 35806 vband so I need to measure and check some part numbers tonight. Usually that catalog is right so I have to check.
Joined: Sep 2003
Posts: 25,895
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
VB500C is the number... i dont know where that link takes you, but when i open it up, I see generic v-band assemblies and under the mild steel option, you can select 5" size
Further down the page you have Borg Warner S series flanges and such but I didnt know those turbos had a specific flange type. I thought all were universal v-bands.
Further down the page you have Borg Warner S series flanges and such but I didnt know those turbos had a specific flange type. I thought all were universal v-bands.
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From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
VB500C is the number... i dont know where that link takes you, but when i open it up, I see generic v-band assemblies and under the mild steel option, you can select 5" size
Further down the page you have Borg Warner S series flanges and such but I didnt know those turbos had a specific flange type. I thought all were universal v-bands.
Further down the page you have Borg Warner S series flanges and such but I didnt know those turbos had a specific flange type. I thought all were universal v-bands.
http://www.pontiaczone.com/forum/showthread.php?t=21535
Supports that 35746 vband is correct and has pictures, but I still think I used the 5.88 inch clamp PN 35806. I will check tonight.
Joined: Sep 2003
Posts: 25,895
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
I had a problem connecting my downpipe to the MP turbo flange. Vband size on that turbo is thick compared to the flange that goes on the downpipe. I just cut my clamp channel in half to allow for that thickflange to fit into the rest of the clamp and it worked just fine.
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Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
I had a problem connecting my downpipe to the MP turbo flange. Vband size on that turbo is thick compared to the flange that goes on the downpipe. I just cut my clamp channel in half to allow for that thickflange to fit into the rest of the clamp and it worked just fine.
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
i was really trying not to cut up anything on this car but in order to fit the downpipe i have to notch the passenger side strut tower.
this was a quick measure job but ill actually have to notch it about 3/4 of an inch higher then the red tape,once i cut it out ill use 1/16th or 1/8th inch plate to back it back in

this was a quick measure job but ill actually have to notch it about 3/4 of an inch higher then the red tape,once i cut it out ill use 1/16th or 1/8th inch plate to back it back in

Joined: Nov 2007
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From: Mechanicsville Virginia
Car: 1989 Turbo Trans Am gta
Engine: 383 78mm turbo
Transmission: Th350 rmvb with brake
Axle/Gears: 9 bolt 3.45s
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
Project89- are you going with a 5" downpipe? is that going to fit behind the passenger side header or are you going to notch the firewall as well?
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
yeah im doing a 5 inch im going to need it for when the vortec headed motor goes in the car. once my mini starter gets here ill see if i have to notch the firewall but i think i can get away without it
this motor is a test motor for now, im going to be ordering up a dart block and building a good 406 , or go right for the 434 stroker kit, vortec heads ,single plane intake converted to efi
Joined: Jul 2003
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From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
Originally Posted by project89
i was really trying not to cut up anything on this car but in order to fit the downpipe i have to notch the passenger side strut tower....
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
i already fired the motor with out the ex manifolds just to make sure my ms was hooked up right and i had the dizzy in and wasnt 180 off,just a quick hit the key see if it fired and shut it right off.
afteter that i pulled the harness again to make some changes to it to get it to lay in a lil neater ,the entire turbo system will be plumbed up sometime next week , im just waiting on my t6 flange and 2.5' vbands to show up along with my 5 inch ex tubing
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
no strut tower notching needed :chacha:, did some mockup today and in these pics i havejust over 5 3/8's clearance between the strut tower and log style header.
now i can order up the actual weld els ill be using and weld the header up


now i can order up the actual weld els ill be using and weld the header up


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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
woot my weld els will be here tomorrow.
anyways now that i am actually able to see the casting number on the block i do not have a sbc 400.
what i have is a 0010 4bolt main .030 over with a factory forged crank
engine code comes back as a 71 truck/bus engine with 255 hp
heads are off atm and so is the oil pan , this motor is getting some good handpicked factory rods that have had arp bolts installed and have been resized and stress relived.
im also goin to throw some pistions in this thing to get a lil bit more compression
flat tops w/4 reliefs and 76cc chambers dont get u a whole lot so im going to step it up to a forged speed pro piston with a .125 dome
with a set of moly rings
im also looking at throwing a cam at it probably oing with something in the 234 duration range with around .515 lift
this thing is going to move when its done woot
anyways now that i am actually able to see the casting number on the block i do not have a sbc 400.
what i have is a 0010 4bolt main .030 over with a factory forged crank
engine code comes back as a 71 truck/bus engine with 255 hp
heads are off atm and so is the oil pan , this motor is getting some good handpicked factory rods that have had arp bolts installed and have been resized and stress relived.
im also goin to throw some pistions in this thing to get a lil bit more compression
flat tops w/4 reliefs and 76cc chambers dont get u a whole lot so im going to step it up to a forged speed pro piston with a .125 dome
with a set of moly rings
im also looking at throwing a cam at it probably oing with something in the 234 duration range with around .515 lift
this thing is going to move when its done woot
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
turbo cleaned up and ready to go
and just got my logs almost done , need to get a 1 5/8's hole saw on monday to drill the holes in the actual log part so i can weld those on



and just got my logs almost done , need to get a 1 5/8's hole saw on monday to drill the holes in the actual log part so i can weld those on



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Engine: 3xx ci tubo
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Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
Looks good. When I do logs I point the weld els in the direction of the flow into the log. I would have rotated the weld els towards the front of the engine. It is a little more work, but I think the flow direction is worth it.
I think you are better off with the 350ci 010 block than the 400ci block.
I think you are better off with the 350ci 010 block than the 400ci block.
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
Looks good. When I do logs I point the weld els in the direction of the flow into the log. I would have rotated the weld els towards the front of the engine. It is a little more work, but I think the flow direction is worth it.
I think you are better off with the 350ci 010 block than the 400ci block.
I think you are better off with the 350ci 010 block than the 400ci block.
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From: erlangen, Germany
Car: 1991 Z28 1LE
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Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
Just curious, but did you ever finish this thing?
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From: Alamogordo, NM
Car: '86 Grand National
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Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
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From: Utah
Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
so far so good except for blowing up transmissions , and taking out one set of head gaskets
on 8psi of boost the car has more power then u need for the street specially in 1st and 2nd even with a 2:73 rear gear , 3rd gear just flat out pulls untill u hit about 4200 rpms then it blows away the back tires
ive made some runs with it at high boost and its flat out scary on the street even with a good tire on the back
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Joined: Mar 2012
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From: suburbs of chicago
Car: subaru wagon, two formula's
Engine: tpi 350's
Transmission: 700 r4
Axle/Gears: 3.27 posi
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
I know this is an older post, but I am doing a twin turbo setup on my formula 350 currently a solid 275hp TPI305 temporary motor till my 357 forged motor is done. I was going to buy this set that dumps the turbos towards the front right next to the serpentine belts, may have to remove the passenger side bracket for the serpentine setup in my 89, but I'll just run a shorter belt and barely get it on, by using a socket and ratcheting the alternator to get the belt on. What kind of manifolds are on this motor? Did they go far to the side of the head, then dumped towards the top? I was going to buy a similar kit for mine. Have you run the car at the track since this setup was finished? I'm very interested, thanks
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Joined: Mar 2012
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From: suburbs of chicago
Car: subaru wagon, two formula's
Engine: tpi 350's
Transmission: 700 r4
Axle/Gears: 3.27 posi
Re: 89 Iroc Sbc400 TPI Megasquirt Single GT45 5-600 rwhp build
I know this is an old post, but how has that twin turbo firebird worked? I saw a different kit from eworld sales, but I like those other turbo headers, I'll just have to mess with the hood, but I also don't wanna do that. Has anyone tried the headers for the turbos that mount the turbos up front, next to the serpentine belt setup?
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Great build... pure and beautiful inspiration 
