C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

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Old Jan 23, 2015 | 11:18 PM
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hey guys, I bought a 1990 c4 for the drivetrain. Im gonna be putting the motor and trans in my 1955 chevy truck (2nd gen) the motor runs and has 118 thousand miles. im wanting to stay with TPI setup and of coure i wanna make it look fancy because it will be a show truck. whats yalls advice on goin through the motor? how much should i go through it? im wanting to put 1.6 roller rockers. thanks in advance for the tips!

cameron
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Old Jan 24, 2015 | 08:15 AM
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If I remember correctly, 1/6 rockers fit but the valve covers need trimming on the drip rails. I an sure others will chime in. By the way, if staying with stock specs, the engine is tourqued out and HP, by about 4800 so no high winding cam. That will be shooting yourself in the foot.
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Old Jan 24, 2015 | 09:05 AM
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(my opinion, and my 2-cents - FWIW) I wouldn't even fool with 1.6 rockers. since your plans are pretty much a show truck, and you're not going to track the thing, might as well keep the 90 L98 pretty much stock. if you want to make it look a little fancy, you could polish the plenum, runners, and intake. there is a company out there that makes old school script center bolt valve covers, again polished, which would show well. I'd ditch the whole air cleaner assembly in favor of a TB mounted K&N, and add a sweet sounding exhaust. to top it off, nice touch would be chevy orange engine paint. if you start monkeying around with the engine's internals, you have to deal with tuning issues. I know guys that put tons of money in their engine, and never take their "show" cars over 50MPH. over compressed, cam'd, and over carb'd, and over geared, and these engines usually run like crap, most guys will say, that's no fun, but I'd keep it user friendly.

Last edited by Joe C; Jan 24, 2015 at 09:08 AM.
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Old Jan 24, 2015 | 09:13 AM
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If the engine is running in the Corvette , I would just listen to it and make sure there are no unusual noises or knocks coming from the motor..It would be a whole lot easier to repair something on a engine stand, then in your truck... I would replace oil pan gasket, rear main seal, valve cover gaskets, and any other gasket you can get to without tearing the motor apart...It would also be a good time to replace the intake gaskets and reseal the china walls with ( the right stuff) because if the intake gaskets are original , they could possibly be leaking soon...If your running an automatic trans, be sure to replace the front seal on the shaft, these should be replaced anything the trans is out of the car......Anther thing, if it were me , I would stay with the 1.5 rockers that are on the motor.. I think changing to higher performance rockers is a bad idea on a motor with that many miles, also, you won't see much difference in performance with just a rocker change...Of course this is just my opinion....Good Luck with the transplant........WW

Last edited by WW7; Jan 24, 2015 at 12:29 PM.
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Old Jan 24, 2015 | 09:28 AM
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118K for that motor is nothing as long as it is not making any unwanted noise or blowing smoke I would just put all new seals and valve cover gaskets and then polish it up or powdercoat it. Theres a guy on ebay that has a powdercoat service for TPI that looks real good.

http://www.ebay.com/itm/TPI-Intake-Tube-Runner-Professional-Powder-Coating-Service-/181287027946?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a358c84ea&vxp=mtr

Last edited by eutu1984; Jan 24, 2015 at 09:29 AM. Reason: spelling
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Old Jan 24, 2015 | 03:45 PM
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Hey guys thanks alot! yeah its gonna be a show truck.. but at the same time i want a little power, If im at a light and some punk wants to race to next light i wanna be able to blow his doors off.. lol not really but i want a little bit! i was thinking about putting a little bigger cam in and like i said doin the lifters.. it would sound good to! what kind of wire harness should i do? i heard i can buy a plug and play type harness that will get rid of alot of the stuff i dont need? thanks!
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Old Jan 24, 2015 | 08:38 PM
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Originally Posted by ghoastrider1
If I remember correctly, 1/6 rockers fit but the valve covers need trimming on the drip rails. I an sure others will chime in. By the way, if staying with stock specs, the engine is tourqued out and HP, by about 4800 so no high winding cam. That will be shooting yourself in the foot.
im gonna get some new taller valve covers. Im wanting to put a little bit bigger cam in so ill remember that! thanks!
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Old Jan 24, 2015 | 08:39 PM
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Originally Posted by eutu1984
118K for that motor is nothing as long as it is not making any unwanted noise or blowing smoke I would just put all new seals and valve cover gaskets and then polish it up or powdercoat it. Theres a guy on ebay that has a powdercoat service for TPI that looks real good.

TPI Intake Tube Runner Professional Powder Coating Service | eBay
Sweet! thanks buddy!
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Old Jan 24, 2015 | 08:41 PM
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Originally Posted by WW7
If the engine is running in the Corvette , I would just listen to it and make sure there are no unusual noises or knocks coming from the motor..It would be a whole lot easier to repair something on a engine stand, then in your truck... I would replace oil pan gasket, rear main seal, valve cover gaskets, and any other gasket you can get to without tearing the motor apart...It would also be a good time to replace the intake gaskets and reseal the china walls with ( the right stuff) because if the intake gaskets are original , they could possibly be leaking soon...If your running an automatic trans, be sure to replace the front seal on the shaft, these should be replaced anything the trans is out of the car......Anther thing, if it were me , I would stay with the 1.5 rockers that are on the motor.. I think changing to higher performance rockers is a bad idea on a motor with that many miles, also, you won't see much difference in performance with just a rocker change...Of course this is just my opinion....Good Luck with the transplant........WW
Well now im thinking about putting a little bit bigger cam in. i might as well have the rings and cam bearings done while im at it.. so ill prob just end up goin through the whole motor. If im gonna spend 50k on this 55 i might as well do the motor right! lol thanks buddy!
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Old Jan 24, 2015 | 08:46 PM
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Originally Posted by Joe C
(my opinion, and my 2-cents - FWIW) I wouldn't even fool with 1.6 rockers. since your plans are pretty much a show truck, and you're not going to track the thing, might as well keep the 90 L98 pretty much stock. if you want to make it look a little fancy, you could polish the plenum, runners, and intake. there is a company out there that makes old school script center bolt valve covers, again polished, which would show well. I'd ditch the whole air cleaner assembly in favor of a TB mounted K&N, and add a sweet sounding exhaust. to top it off, nice touch would be chevy orange engine paint. if you start monkeying around with the engine's internals, you have to deal with tuning issues. I know guys that put tons of money in their engine, and never take their "show" cars over 50MPH. over compressed, cam'd, and over carb'd, and over geared, and these engines usually run like crap, most guys will say, that's no fun, but I'd keep it user friendly.
I think the only thing i wanna do to the motor as internals is maybe a little bit bigger cam.. my dad pulled a motor like this and put it in a c-10 he kept everything stock besides the cam and rockers and it just made it a full roller motor. but doin the cam ill have to have cam bearings done? and might as well have them do the rings? thanks on the (looks) advice! i like the orange ideal! the truck is gonna have tons of money but i promise it will go over 50mph! lol
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Old Jan 24, 2015 | 08:59 PM
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Originally Posted by samples45
i want a little power, If im at a light and some punk wants to race to next light i wanna be able to blow his doors off.
what are your plans for traction in the rear? Mroe power is cool, but that stock motor will spin 'em just fine, probably in at least three gears, depending on the setup.

I'm doing this with a '55 F100 which is reportedly 700# lighter than the C4 the driveline came from. I am glad to have the 3.07 ratio, which should be quick enough for my wants and deliver decent consumption behind the 700R4. the L83 is carbed and built with an 'RV' cam, for torque.
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Old Jan 24, 2015 | 09:04 PM
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Originally Posted by whalepirot
what are your plans for traction in the rear? Mroe power is cool, but that stock motor will spin 'em just fine, probably in at least three gears, depending on the setup.

I'm doing this with a '55 F100 which is reportedly 700# lighter than the C4 the driveline came from. I am glad to have the 3.07 ratio, which should be quick enough for my wants and deliver decent consumption behind the 700R4. the L83 is carbed and built with an 'RV' cam, for torque.
55 F100 weighs about 1000 lbs more than a C4 corvette.
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Old Jan 24, 2015 | 09:09 PM
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Originally Posted by eutu1984
55 F100 weighs about 1000 lbs more than a C4 corvette.
oK. I quoted the shop that engineered and installed the frame adaptation and components and never checked until now.

Online references: 1984 C4 auto:3,192#; 1955 F100 V8: 3460 lb.

Last edited by whalepirot; Jan 24, 2015 at 09:17 PM.
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Old Jan 24, 2015 | 09:14 PM
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Originally Posted by whalepirot
oK. Not according to the shop that engineered and installed the frame adaptation and components.
A C4 weighs about 3300 lbs. and 55 F100 weighs about 4500 lbs. you can google it.
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Old Jan 24, 2015 | 09:46 PM
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Correct truck weights:
1954 - 1955 F-100 6 cyl. = 3,080 lbs.

1956 F-100 6.5 ft bed, 6 cyl. = 3,070 lbs.
1956 F-100 8 ft bed, 6 cyl. = 3,225 lbs.

1957 F-100 6.5 ft styleside bed, 6 cyl. = 3,110 lbs.
1957 F-100 6.5 ft flareside bed, 6 cyl. = 3,120 lbs.
1957 F-100 8 ft styleside bed, 6 cyl. = 3,285 lbs.
1957 F-100 8 ft flareside bed, 6 cyl. = 3,295 lbs.

OP, At the minimum suggest a valve job + head resurface & new timing chain & gears.
Cams: If more than .500 lift @ the valve the heads will need to be machined for guide to retainer/oil seal clearance.

Last edited by Churchkey; Jan 24, 2015 at 09:49 PM.
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Old Jan 24, 2015 | 10:02 PM
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Originally Posted by whalepirot
what are your plans for traction in the rear? Mroe power is cool, but that stock motor will spin 'em just fine, probably in at least three gears, depending on the setup.

I'm doing this with a '55 F100 which is reportedly 700# lighter than the C4 the driveline came from. I am glad to have the 3.07 ratio, which should be quick enough for my wants and deliver decent consumption behind the 700R4. the L83 is carbed and built with an 'RV' cam, for torque.
yeah that 55 f1 is heavy! lol! I have a disk brake posi with 3:73 gears right now.. dont know how thats gonna work yet!
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Old Jan 24, 2015 | 10:06 PM
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Originally Posted by Churchkey
Correct truck weights:
1954 - 1955 F-100 6 cyl. = 3,080 lbs.

1956 F-100 6.5 ft bed, 6 cyl. = 3,070 lbs.
1956 F-100 8 ft bed, 6 cyl. = 3,225 lbs.

1957 F-100 6.5 ft styleside bed, 6 cyl. = 3,110 lbs.
1957 F-100 6.5 ft flareside bed, 6 cyl. = 3,120 lbs.
1957 F-100 8 ft styleside bed, 6 cyl. = 3,285 lbs.
1957 F-100 8 ft flareside bed, 6 cyl. = 3,295 lbs.

OP, At the minimum suggest a valve job + head resurface & new timing chain & gears.
Cams: If more than .500 lift @ the valve the heads will need to be machined for guide to retainer/oil seal clearance.
yeah i think im just gonna go through the whole motor! if im gonna have it out might as well get the heads done and replace all the seals, bearings and gaskets. Im in no hurry so might as well do it right! my problems are gonna be with the TPI setup.. ive never messed with that stuff and really dont wanna go carb. im gonna try and find a simple plug and play harness and hopefully i wont throw to many things!! lol
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To advice please!

Old Jan 24, 2015 | 10:15 PM
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Originally Posted by Churchkey
Correct truck weights:
1954 - 1955 F-100 6 cyl. = 3,080 lbs.

1956 F-100 6.5 ft bed, 6 cyl. = 3,070 lbs.
1956 F-100 8 ft bed, 6 cyl. = 3,225 lbs.

1957 F-100 6.5 ft styleside bed, 6 cyl. = 3,110 lbs.
1957 F-100 6.5 ft flareside bed, 6 cyl. = 3,120 lbs.
1957 F-100 8 ft styleside bed, 6 cyl. = 3,285 lbs.
1957 F-100 8 ft flareside bed, 6 cyl. = 3,295 lbs.

OP, At the minimum suggest a valve job + head resurface & new timing chain & gears.
Cams: If more than .500 lift @ the valve the heads will need to be machined for guide to retainer/oil seal clearance.
Thats amazing there that light, thats about the same as my 4 cyl. S10.
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Old Jan 25, 2015 | 02:55 AM
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Originally Posted by samples45
my problems are gonna be with the TPI setup.. ive never messed with that stuff and really dont wanna go carb. im gonna try and find a simple plug and play harness and hopefully i wont throw to many things!! lol
The 90 Corvette uses a speed density system, basically no mass air flow in the intake air tube.

For a good plug/play engine management system suggest looking @ Howell products. I have used several of their systems in street rod builds. If the donor car ran ok you may be able to use its computer & save some $$$.

http://howellefi.com/gm-tpi-products...nesses-en.html

Be sure to check the fuel injectors to determine if they have been changed. 90's come with multi-tech injectors they fail due to corn gas.
The injection operating system is "batch fire", If one injector fails electrically it may stop several or all of the injectors from operating. Normally cold start will be ok the issues occur when the engine gets to operating temp.
Many here including myself have changed to Bosch 111 injectors available from Jon @FIC.

FIC contact info + spray pattern video here:
https://www.corvetteforum.com/forums...questions.html

Last edited by Churchkey; Jan 25, 2015 at 03:02 AM. Reason: Add text
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Old Jan 25, 2015 | 01:42 PM
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Originally Posted by Churchkey
The 90 Corvette uses a speed density system, basically no mass air flow in the intake air tube.

For a good plug/play engine management system suggest looking @ Howell products. I have used several of their systems in street rod builds. If the donor car ran ok you may be able to use its computer & save some $$$.

http://howellefi.com/gm-tpi-products...nesses-en.html

Be sure to check the fuel injectors to determine if they have been changed. 90's come with multi-tech injectors they fail due to corn gas.
The injection operating system is "batch fire", If one injector fails electrically it may stop several or all of the injectors from operating. Normally cold start will be ok the issues occur when the engine gets to operating temp.
Many here including myself have changed to Bosch 111 injectors available from Jon @FIC.

FIC contact info + spray pattern video here:
https://www.corvetteforum.com/forums...questions.html
Hey thansk alot man! learned some stuff i wasnt for sure on! what about the TB its self? could i replace that with a aftermarket one? or should i?
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