406 and a disc rear into a '99 Suburban K1500
July 1st, 2011, 5:53 PM
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406 and a disc rear into a '99 Suburban K1500
Sorry - newbie here, so be gentle...
My wife uses our 199 GMC Suburban K1500 for around-town driving and errands (family truckster) and I use it to tow my 24' enclosed race trailer from our home on LI to places like Watkins Glen, Limerock, Pocono, NJMP, Summit Point, and other local race tracks. When we hit anything more then a hill, the truck struggles to drag the 10K lbs of trailer (usually less, but that is the max) and I end up in the right lane at 3500 RPM (nervous about holding it higher for long periods) and about 45 MPH with the flashers going. I have added a remote rear airbag system and added a T/A cover on the rear for added strength and my truck has the factory towing package with 3.73:1 gearing and a trans cooler, but none of these address the fact it is just a little underpowered for the job. Other than this issue, it is in great shape and I maintain it religiously. I recently replaced the transfer case after it wore a hole in one of the case halves (common to the NP246) and the trans shifts strong and fluid is perfect.
I have a 406 cu in SBC that I originally built for a Chevelle bracket racer, but since sold that car and the top 1/2 of the motor. I still have the shortblock, which was internally balanced and had many upgrades including forged pistons that were yielding a bit over 10:1 compression with the small chamber AFR heads that the motor originally had.
My plan is to add a set of good Vortec iron heads to the motor, maybe get an intake off another '99 suburban, and build a motor I can swap in for the stock 350 which has over 165K now and burns about 1 qt every 2K miles, or 1K miles if towing or driving hard. It may still have some life left, but since it is a daily driver, I cannot afford to let it break down, so trying to be proactive here...
My concern is how the GM EFI system will handle the extra displacement? I'm assuming it might compensate automatically, based on increased flow numbers from the MAF, etc. However, not all systems have the same degrees of flexibility and I'd like to understand what challenges I may face, so I can prepare for them versus have this turn into a nightmare.
Can anyone tell me what I need to do to ensure that the 406 does the following:
> Just bolts in - assuming I use the Vortec heads all the accessories should just work, right? Anything I need to worry about?
> Just runs and is drivable without any major reprogramming or other tuning? Is this realistic or do I need to plan to get a Superchips, Predator, or tuning day with a local shop?
> Will not struggle to deliver the extra fuel for the 56 cu in increase in displacement. Do I need to up-size injectors, fuel pump, or anything?
I would also like some suggestions on the following:
> What exhaust would make sense and fit in the truck. I replaced the cat-back system about 18 months ago, but would be interested in going to true duals if there is a recipe to do this without spending a fortune.
> What cam to use? I really want to make over 400 ft lbs of tq, maybe 450. Horsepower is of little interest as I have a small collection of race cars and they are at least 400 horsepower and one is nearly 2X that number.
> Are the iron Vortecs enough or is there a better value (perf/dollar)? I do not care about weight savings, not worried about detonation (I will run premium fuel if needed), and I wont be opening the hood except for maintenance.
Lastly, I am thinking of upgrading to disc brakes in the rear as well - wondering if it is easier to get a newer rear and swap it in, especially since mine is OE and there was a decent amount of metal in the fluid the last time I drained it about 2 months ago. I am not afraid to cut/weld perches if that is what's needed.
My wife uses our 199 GMC Suburban K1500 for around-town driving and errands (family truckster) and I use it to tow my 24' enclosed race trailer from our home on LI to places like Watkins Glen, Limerock, Pocono, NJMP, Summit Point, and other local race tracks. When we hit anything more then a hill, the truck struggles to drag the 10K lbs of trailer (usually less, but that is the max) and I end up in the right lane at 3500 RPM (nervous about holding it higher for long periods) and about 45 MPH with the flashers going. I have added a remote rear airbag system and added a T/A cover on the rear for added strength and my truck has the factory towing package with 3.73:1 gearing and a trans cooler, but none of these address the fact it is just a little underpowered for the job. Other than this issue, it is in great shape and I maintain it religiously. I recently replaced the transfer case after it wore a hole in one of the case halves (common to the NP246) and the trans shifts strong and fluid is perfect.
I have a 406 cu in SBC that I originally built for a Chevelle bracket racer, but since sold that car and the top 1/2 of the motor. I still have the shortblock, which was internally balanced and had many upgrades including forged pistons that were yielding a bit over 10:1 compression with the small chamber AFR heads that the motor originally had.
My plan is to add a set of good Vortec iron heads to the motor, maybe get an intake off another '99 suburban, and build a motor I can swap in for the stock 350 which has over 165K now and burns about 1 qt every 2K miles, or 1K miles if towing or driving hard. It may still have some life left, but since it is a daily driver, I cannot afford to let it break down, so trying to be proactive here...
My concern is how the GM EFI system will handle the extra displacement? I'm assuming it might compensate automatically, based on increased flow numbers from the MAF, etc. However, not all systems have the same degrees of flexibility and I'd like to understand what challenges I may face, so I can prepare for them versus have this turn into a nightmare.
Can anyone tell me what I need to do to ensure that the 406 does the following:
> Just bolts in - assuming I use the Vortec heads all the accessories should just work, right? Anything I need to worry about?
> Just runs and is drivable without any major reprogramming or other tuning? Is this realistic or do I need to plan to get a Superchips, Predator, or tuning day with a local shop?
> Will not struggle to deliver the extra fuel for the 56 cu in increase in displacement. Do I need to up-size injectors, fuel pump, or anything?
I would also like some suggestions on the following:
> What exhaust would make sense and fit in the truck. I replaced the cat-back system about 18 months ago, but would be interested in going to true duals if there is a recipe to do this without spending a fortune.
> What cam to use? I really want to make over 400 ft lbs of tq, maybe 450. Horsepower is of little interest as I have a small collection of race cars and they are at least 400 horsepower and one is nearly 2X that number.
> Are the iron Vortecs enough or is there a better value (perf/dollar)? I do not care about weight savings, not worried about detonation (I will run premium fuel if needed), and I wont be opening the hood except for maintenance.
Lastly, I am thinking of upgrading to disc brakes in the rear as well - wondering if it is easier to get a newer rear and swap it in, especially since mine is OE and there was a decent amount of metal in the fluid the last time I drained it about 2 months ago. I am not afraid to cut/weld perches if that is what's needed.
Last edited by pcking; July 1st, 2011 at 5:55 PM.
July 1st, 2011, 7:54 PM
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Welcome to the forum.
I've heard that a good RV cam has good torque. Not sure how much adaptability the '99 ECMs had. Somebody on this forum probably knows tho. But if you have a local programming shop, then they'd know. A lot better option than a "one size fits all" chip.
What kind of race car?
I've heard that a good RV cam has good torque. Not sure how much adaptability the '99 ECMs had. Somebody on this forum probably knows tho. But if you have a local programming shop, then they'd know. A lot better option than a "one size fits all" chip.
What kind of race car?
July 2nd, 2011, 8:59 AM
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I heard the same about the RV cams, but not familiar with any of the grinds - used to making RPM and horsepower vs. low-end torque, so a bit lost.
And my local tuner is a bit pricey, so I was trying to avoid involving him and dumping my wallet out into his cash register.
As for the race cars, I have too many, and I recently downsized. Aside from the '99 GMC, I have...
> 1971 Chevelle Drag Car - 355 SBC w/150 NX Gemini Twin nitrous kit - ~550 HP, runs 11's without the spray and mid-to-low 10's with it.
> 1988 Mustang Road Racer - roller 302 w/ FRPP Turboswirl heads and Paxton Supercharger making up to 14 psi of boost, tubular front suspension, panhard bar, 12-point DOM cage, and more... no idea on power but top speed of over 150 MPH
> 1989 Ford Escort GT Stock Car - full roll cage, ported head, custom cam, suspension mods for camber/caster, lexan windshield, battery relocated, and Kirkey race seat. Compete in 4-cylinder enduros at local circle track
> 1969 AMC AMX -- original matching numbers 390 cu in w/ close ratio 4 speed, 3.54 twin grip, and factory AMC/Edelbrock intake - estimated 475 HP / 600 ft lb (my baby)
> 2006 Dodge Charger R/T w/ Road & Track package - CIA, low temp stat, hi-flow exhaust, Superchips, chin spoiler/rear air diffuser, makes ~400 HP and 435 TQ at the flywheel - my everyday driver...
Used to have have a '91 Mustang GT with a 408 stroker that ran 11 flat on motor, another '88 Mustang Road Racer (even more sinister) that I sold to buy the AMX, and a '67 Chevelle roller that I sold to buy the '71 I have now. And I race in the 24 Hours of Lemons series in a friends VW (great fun, anyone can race cheap).
What about you?
And my local tuner is a bit pricey, so I was trying to avoid involving him and dumping my wallet out into his cash register.
As for the race cars, I have too many, and I recently downsized. Aside from the '99 GMC, I have...
> 1971 Chevelle Drag Car - 355 SBC w/150 NX Gemini Twin nitrous kit - ~550 HP, runs 11's without the spray and mid-to-low 10's with it.
> 1988 Mustang Road Racer - roller 302 w/ FRPP Turboswirl heads and Paxton Supercharger making up to 14 psi of boost, tubular front suspension, panhard bar, 12-point DOM cage, and more... no idea on power but top speed of over 150 MPH
> 1989 Ford Escort GT Stock Car - full roll cage, ported head, custom cam, suspension mods for camber/caster, lexan windshield, battery relocated, and Kirkey race seat. Compete in 4-cylinder enduros at local circle track
> 1969 AMC AMX -- original matching numbers 390 cu in w/ close ratio 4 speed, 3.54 twin grip, and factory AMC/Edelbrock intake - estimated 475 HP / 600 ft lb (my baby)
> 2006 Dodge Charger R/T w/ Road & Track package - CIA, low temp stat, hi-flow exhaust, Superchips, chin spoiler/rear air diffuser, makes ~400 HP and 435 TQ at the flywheel - my everyday driver...
Used to have have a '91 Mustang GT with a 408 stroker that ran 11 flat on motor, another '88 Mustang Road Racer (even more sinister) that I sold to buy the AMX, and a '67 Chevelle roller that I sold to buy the '71 I have now. And I race in the 24 Hours of Lemons series in a friends VW (great fun, anyone can race cheap).
What about you?
July 3rd, 2011, 12:06 AM
#4
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Might give Comp Cams a call re: RV cams.
Blackbear Performance might be a reasonable way to get your ECM programmed but not sure. Give Justin a call.
No race cars, just my '73 Corvette that I used to autoX but currently rebuilding front suspension before I put the rebuilt engine back in.
Blackbear Performance might be a reasonable way to get your ECM programmed but not sure. Give Justin a call.
No race cars, just my '73 Corvette that I used to autoX but currently rebuilding front suspension before I put the rebuilt engine back in.
July 3rd, 2011, 9:24 AM
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Nice -a '72 'vette is a very cool car and using it at the AutoX is sure to draw a crowd.
Thanks for the advice, I'll reach out to Comp and Blackbear after the holiday weekend.
Enjoy the 4th!
Thanks for the advice, I'll reach out to Comp and Blackbear after the holiday weekend.
Enjoy the 4th!
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