Hello

[572SS]

New to the board, just thought I would say hi!

Latest project is a GMPP 572/620 in my 1990 454SS pickup truck! Took a little work but we got her in, still a few tuning issues.

Al

[dhardison]

Welcome! Nice engine :woot:

[sunkistcamaro]

Welcome to the site!

[572SS]

Thanks guys!

Dan, I was following your Demon, demon's a bit. Glad to hear you got them sorted out! I still have a few tuning issues as well, mainly hard starting. Did you use the ported vacuum for the vacuum advance and did you HEI come with a rev limiter? I have a pretty early 572 and mine didn't come with a limiter. The hard starting seemed to come after I changed to an MSD HEI module.

The power seems pretty good. The 1990 454SS is no light weight at around 4300-4400#! I'm running Super Comps 2" into 3 1/2" collectors with 3" Flowmaster Super 40's and 3" pipes both out the passenger side just in front of the rear wheel. We had to do alot of cutting to get a good fit on the headers! We also had to hump the cross-member on both sides. The tranny is a built TH-375 with around 2,200-2,300 stall and a GM 14 bolt with 3.73 gears! I have yet to do a full tilt run with it yet but the 295/65/15 BFG drag radials seem to hold it pretty well so far.

Al

[Ralph LoGrasso]

Welcome to the site, Al. Sounds like a cool truck--post some pictures if you can.

[572SS]

The Vette had been apart for some time now, long story!

Al

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[dhardison]

Thanks guys!

Dan, I was following your Demon, demon's a bit. Glad to hear you got them sorted out! I still have a few tuning issues as well, mainly hard starting. Did you use the ported vacuum for the vacuum advance and did you HEI come with a rev limiter? I have a pretty early 572 and mine didn't come with a limiter. The hard starting seemed to come after I changed to an MSD HEI module.

The power seems pretty good. The 1990 454SS is no light weight at around 4300-4400#! I'm running Super Comps 2" into 3 1/2" collectors with 3" Flowmaster Super 40's and 3" pipes both out the passenger side just in front of the rear wheel. We had to do alot of cutting to get a good fit on the headers! We also had to hump the cross-member on both sides. The tranny is a built TH-375 with around 2,200-2,300 stall and a GM 14 bolt with 3.73 gears! I have yet to do a full tilt run with it yet but the 295/65/15 BFG drag radials seem to hold it pretty well so far.

AlAl, Yes, my distributor did come with a rev limiter. The instructions I received stated NOT to use the vacuum advance whatsoever.

When the GMPP engineers came down from MI to look at my issues, they drove a early-mid 90s K1500 longbed with the 572/620 and a 4L80E trans. They took me for a quick ride on the highway and it pulled pretty good. Not sure what gears they were running but they seemed pretty low (numerically). With your 3.73s your's should run really well.

[Tech @ BG]

Al, Yes, my distributor did come with a rev limiter. The instructions I received stated NOT to use the vacuum advance whatsoever.

When the GMPP engineers came down from MI to look at my issues, they drove a early-mid 90s K1500 longbed with the 572/620 and a 4L80E trans. They took me for a quick ride on the highway and it pulled pretty good. Not sure what gears they were running but they seemed pretty low (numerically). With your 3.73s your's should run really well.

Dan,

Was it a green 2-Door truck by chance?

[dhardison]

Dan,

Was it a green 2-Door truck by chance? Yep, an extended cab with white, orange and yellow striped graphics on the back. You've seen it?

[Tech @ BG]

If it was that Teal green color... It's probably the one that Roush used for drivability testing when they developed that engine.

[dhardison]

If it was that Teal green color... It's probably the one that Roush used for drivability testing when they developed that engine. Yes, that's the one. The 572 looked ROUGH but ran pretty well. They drove it from Detroit, MI to Columbus, OH then somewhere in PA and back to MI. Rusty said it pulled down ~10-12mpg.

[572SS]

Yes, that's the one. The 572 looked ROUGH but ran pretty well. They drove it from Detroit, MI to Columbus, OH then somewhere in PA and back to MI. Rusty said it pulled down ~10-12mpg.

I'm sure the 4L80E helped the mpg, I'm getting no where near that! I got almost 13 mpg @ 80 mph with a 580 hp 496 in the SS. The 496 had a 950 Holley HP with vac sec. That was with 31" tall tires, it still sucked around town! The last setup I had got better than stock, a little over 13 on the road and 9-10 around town if you stayed out of it! It would run a 13.00 @ 106 right off the freeway! It was TBI, Edelbrock intake, cam and shorty headers with 781 heads and a little S-Trim Vortech! Nice setup, I ran it lean and broke a piston!
:seizure:

Al

[Tech @ BG]

Yes, that's the one. The 572 looked ROUGH but ran pretty well. They drove it from Detroit, MI to Columbus, OH then somewhere in PA and back to MI. Rusty said it pulled down ~10-12mpg.

Not sure what's been done to it since then, but the Roush boys would leave it outside overnight in MI in Jan. to make sure they could get it to start right.