73 454 swap into 93 K2500 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**WIDESIDE72** · 12-10-2011, 11:02 PM

I have a 93 GMC K2500. I bought the truck with 200k miles and a blown TBI 350. I swapped in a 97 Vortec 350 with 80k miles, using a Crusader Marine intake to adapt the TBI to the Vortec heads,then proceeded to spin two main bearings. I bought a rebuilt 350 short block and I installed a Comp 4x4 grind torque cam ( I forget the specs) beehive springs, full roller rockers, rebuilt TB from RV Morse machine with ported bores, button heads on butterflys, flow matched injectors, fuel pump for a Vortec truck and a regulator bumped fuel pressure to 15 psi at full throttle, full length Hedman headers, full 2 1/2" dual exhaust with Dyanflow cats, MSD 6A. Brian at TBICHIPS.COM burnedme a custom chip for the combo.The 350 still doesn't have the power I need to pull a loaded 18 ft car hauler. (A 3/4 ton 4x4 is a heavy truck for a 350 to pull around unloaded!)

I recently scored a rebuilt 454 (468?) out of a 73 Cheyenne for cheap. The engine runs great, but is stock. It still has a points distributor and low profile cast iron intake. I am thinking of slipping a good RV cam into it and already scored an Edelbrock Performer intake from this site. I will also add a set of full length 1 3/4" headers.

My main question is the flywheel. I believe the 350 has an external balance flywheel. Can I use this same flywheel on the 454? I don't think so. I think I need a 454 flywheel. Should I specify a standard transflywheel for a '73 engine? Will it be compatible with the existing clutch and NV4500 trans? Or should I spec a 93 flywheel?

Also, I am trying to decide on sticking with TBI or going to a carb. I have the Quadrajet that came with the engien, and a Holley 750 dp. (I know that the 750 on a 454 will run like a bat outa hell). I can't help but thinking that the TBI on the existing 350 is what is holding me back, and if I put it on the 454, it will also be the limiting factor. I don't want to spend money on the larger 454 TB only to be disappointed.

WHere I live I am not subject to smog testing where the truck is registered, only the visual and drive. Does anyony have experience when swapping from TBI to a carb and passing insection?

**WIDESIDE72** · 12-10-2011, 11:04 PM

In plan to use the 350 in my 55 Chevy 1st series pickup on an 85 s10 lwb chassis along with a 700r4 and an Explorer 8.8" rear with 4.10 posi, if I don't sell it first!

Buckeye Puller · 12-11-2011, 01:12 PM

You should get the flywheel for the 1973 454. The 73 454 has a 2 piece rear main seal and a 93 454 would have a 1 piece rear main seal so the bolt pattern is not the same on the crank flange. Get the clutch set for the 1973 454 with the 4 speed(SM465). It will be the same spline as the nv4500(Both are 10 spline by 1 1/8" shaft). As for the carb or tbi, Im a fuel injection fan, BUT the tbi will not make as much horsepower as the carb will. If I was going to have to chose between the Q-jet or the Holley, I would go with the Holley. Q-jets are ok but the Holley is more tuner friendly IMO.

bloertcher · 12-11-2011, 01:33 PM

Either clutch set should work,I would personally use one from the 93,just to be sure it will play nice with the hydraulic release assembly.
Carb or EFI,that's a really tough call to make.TBI is rock solid,reliable,and user friendly.
However,I've never met anyone who considered it easy to tune for modifications.I am going to regurgitate some knowledge that I've gained from 3rd gen. Camaro buddies who have built up TBI engines.
While TBI chips is a good place to get a performance chip,there is no way to get an ideal tune without data logging the vehicle itself.Every guy I've ever known to be successful at tuning a TBI engine for performance,burned multiple chips before they nailed the tune.
As one friend explained it to me,nobody could dial in a carb on a bench,mail it to the owner,and it be perfectly tuned.Same goes for a TBI chip.
If it were my choice to make,I would decide if maximum performance or maximum drivability were my priority.If you can live with the nature of a carb in cold weather,altitude changes,etc. than it will make better power than a TBI.
If I decided to stay TBI,I would make no changes to the engine other than the intake/headers you have mentioned.Even the slightest camshaft change can throw a TBI into a whirlwind.
My truck has a mild 350,that is carbed,but it began life a a 6.5 diesal weezer,so going with a carb was just much simpler.
Had it started out a TBI truck,I'd have likely put a TBI 454 in it.
Just my thoughts on it,but then again advice is always worth what it costs.

**WIDESIDE72** · 12-11-2011, 05:51 PM

I figure that I will need to buy a new manual trans flywheel for the 454. I wasn't sure whether the 93 454's were one piece rear main seals like 87 up small blocks or not. I will try and use the existing clutch and pressure plate, as it is a fairly new Ram setup that I scored on EBay for $75 shipped (!)

Thanks everyone for the input so far. The carb vs TBI dilemna still has me up in the air. I need to talk with some Texas folks to get input on the state inspection issues with removing the TBI for a carb. I am thinking that I might buy an adapter to mount the 350 throttle body on the Performer carb intake and see how it goes. I already have a $250 chip in the computer that was tuned with for the 350 with the mods I mentioned above. I am sure that the same ship will not like the bigger engine. I might go so far as to get another chiop burned and give the TBI a chance. I am just trying not to get too much $$$ into this deal, as it is not a daily driven truck. I only use it ocassionally.

**WIDESIDE72** · 12-11-2011, 05:58 PM

I also have a 1991 Olds Custom Cruiser wagon project that I will be pulling the TBI 305 and 700r4 out of. I plan to swap in a 1994 Caprice 9C1 LT1 and 4L60E along with all of the necessary wiring and computer for the LT1 and 4L60E. My plan is to put the Vortec/ TBI Frankenstein engine into my 55 Chevy 1st series that is sitting on a 1985 S10 LWB chassis and use the wiring and computer out of either the 93 GMC truck, or the wiring out of the 91 Olds and 93 truck computer...At least this built up 350 will not go to waste. It should have more than enough power in a light weight truck like the 55. I know I have a screw loose.

12-10-2011, 11:02 PM	#1
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	73 454 swap into 93 K2500 I have a 93 GMC K2500. I bought the truck with 200k miles and a blown TBI 350. I swapped in a 97 Vortec 350 with 80k miles, using a Crusader Marine intake to adapt the TBI to the Vortec heads,then proceeded to spin two main bearings. I bought a rebuilt 350 short block and I installed a Comp 4x4 grind torque cam ( I forget the specs) beehive springs, full roller rockers, rebuilt TB from RV Morse machine with ported bores, button heads on butterflys, flow matched injectors, fuel pump for a Vortec truck and a regulator bumped fuel pressure to 15 psi at full throttle, full length Hedman headers, full 2 1/2" dual exhaust with Dyanflow cats, MSD 6A. Brian at TBICHIPS.COM burnedme a custom chip for the combo.The 350 still doesn't have the power I need to pull a loaded 18 ft car hauler. (A 3/4 ton 4x4 is a heavy truck for a 350 to pull around unloaded!) I recently scored a rebuilt 454 (468?) out of a 73 Cheyenne for cheap. The engine runs great, but is stock. It still has a points distributor and low profile cast iron intake. I am thinking of slipping a good RV cam into it and already scored an Edelbrock Performer intake from this site. I will also add a set of full length 1 3/4" headers. My main question is the flywheel. I believe the 350 has an external balance flywheel. Can I use this same flywheel on the 454? I don't think so. I think I need a 454 flywheel. Should I specify a standard transflywheel for a '73 engine? Will it be compatible with the existing clutch and NV4500 trans? Or should I spec a 93 flywheel? Also, I am trying to decide on sticking with TBI or going to a carb. I have the Quadrajet that came with the engien, and a Holley 750 dp. (I know that the 750 on a 454 will run like a bat outa hell). I can't help but thinking that the TBI on the existing 350 is what is holding me back, and if I put it on the 454, it will also be the limiting factor. I don't want to spend money on the larger 454 TB only to be disappointed. WHere I live I am not subject to smog testing where the truck is registered, only the visual and drive. Does anyony have experience when swapping from TBI to a carb and passing insection?

12-10-2011, 11:04 PM	#2
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: 73 454 swap into 93 K2500 In plan to use the 350 in my 55 Chevy 1st series pickup on an 85 s10 lwb chassis along with a 700r4 and an Explorer 8.8" rear with 4.10 posi, if I don't sell it first!

12-11-2011, 01:12 PM	#3
Buckeye Puller Registered User Join Date: Jun 2011 Location: Thurman, Ohio Posts: 10	Re: 73 454 swap into 93 K2500 You should get the flywheel for the 1973 454. The 73 454 has a 2 piece rear main seal and a 93 454 would have a 1 piece rear main seal so the bolt pattern is not the same on the crank flange. Get the clutch set for the 1973 454 with the 4 speed(SM465). It will be the same spline as the nv4500(Both are 10 spline by 1 1/8" shaft). As for the carb or tbi, Im a fuel injection fan, BUT the tbi will not make as much horsepower as the carb will. If I was going to have to chose between the Q-jet or the Holley, I would go with the Holley. Q-jets are ok but the Holley is more tuner friendly IMO.

12-11-2011, 01:33 PM	#4
bloertcher Registered User Join Date: Jul 2003 Location: Springfield,Mo. Posts: 305	Re: 73 454 swap into 93 K2500 Either clutch set should work,I would personally use one from the 93,just to be sure it will play nice with the hydraulic release assembly. Carb or EFI,that's a really tough call to make.TBI is rock solid,reliable,and user friendly. However,I've never met anyone who considered it easy to tune for modifications.I am going to regurgitate some knowledge that I've gained from 3rd gen. Camaro buddies who have built up TBI engines. While TBI chips is a good place to get a performance chip,there is no way to get an ideal tune without data logging the vehicle itself.Every guy I've ever known to be successful at tuning a TBI engine for performance,burned multiple chips before they nailed the tune. As one friend explained it to me,nobody could dial in a carb on a bench,mail it to the owner,and it be perfectly tuned.Same goes for a TBI chip. If it were my choice to make,I would decide if maximum performance or maximum drivability were my priority.If you can live with the nature of a carb in cold weather,altitude changes,etc. than it will make better power than a TBI. If I decided to stay TBI,I would make no changes to the engine other than the intake/headers you have mentioned.Even the slightest camshaft change can throw a TBI into a whirlwind. My truck has a mild 350,that is carbed,but it began life a a 6.5 diesal weezer,so going with a carb was just much simpler. Had it started out a TBI truck,I'd have likely put a TBI 454 in it. Just my thoughts on it,but then again advice is always worth what it costs. __________________ RIP Baby Jack 2-06-07 See You On The Other Side My Little Man

12-11-2011, 05:51 PM	#5
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: 73 454 swap into 93 K2500 I figure that I will need to buy a new manual trans flywheel for the 454. I wasn't sure whether the 93 454's were one piece rear main seals like 87 up small blocks or not. I will try and use the existing clutch and pressure plate, as it is a fairly new Ram setup that I scored on EBay for $75 shipped (!) Thanks everyone for the input so far. The carb vs TBI dilemna still has me up in the air. I need to talk with some Texas folks to get input on the state inspection issues with removing the TBI for a carb. I am thinking that I might buy an adapter to mount the 350 throttle body on the Performer carb intake and see how it goes. I already have a $250 chip in the computer that was tuned with for the 350 with the mods I mentioned above. I am sure that the same ship will not like the bigger engine. I might go so far as to get another chiop burned and give the TBI a chance. I am just trying not to get too much $$$ into this deal, as it is not a daily driven truck. I only use it ocassionally.

12-11-2011, 05:58 PM	#6
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: 73 454 swap into 93 K2500 I also have a 1991 Olds Custom Cruiser wagon project that I will be pulling the TBI 305 and 700r4 out of. I plan to swap in a 1994 Caprice 9C1 LT1 and 4L60E along with all of the necessary wiring and computer for the LT1 and 4L60E. My plan is to put the Vortec/ TBI Frankenstein engine into my 55 Chevy 1st series that is sitting on a 1985 S10 LWB chassis and use the wiring and computer out of either the 93 GMC truck, or the wiring out of the 91 Olds and 93 truck computer...At least this built up 350 will not go to waste. It should have more than enough power in a light weight truck like the 55. I know I have a screw loose.



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