so i am picking up a corvette L98 complete engine with MAF but i am unsure wheather to convert it to tbi for a clean easy(ish) swap or just do a carb swap and call it a day? i am unsure if this is the aluminum head version, the valve covers are off and the valve cover gasket surface on the head was shiny and silver but the car is claimed to be an 85? and ideas? yes i am in cali but it will be reg in ohio before the swap is done, i am just planning to do a cam and minor port job and swap injection setup then drop it in... btw how many times can i hammer it until the rear and trans give? the bird is a 91 XS with 700r4 and non limited slip rear. 114k mi on all original car...? i just put on my ultimate tbi today nd was very impressed with the free performance gain.

 

What year did it come out off ? Did you buy yet I would recommend researching first before you spend money

IIRC 80 sumthing i could be wrong on the year but was only year with iron heads

For TBi/intake is a limiting factor you will need to get chip burn http://www.tbichips.com/ IIRC on the ultimate tbi mod tbi can handle 350is hp I think
If you go carb get a different intake and if carb tune right should perform better

700r4 can't take much once you swap l98 especially if you don't have trans cooler heat is its enemy and will lose gears or break a fwd sprag etc I've broke several I recommend getting rebuilt kit from 700r4l60e.com good guy I recommend rebuilding trans and using trans cooler or atleast install one rebuild later

You have 305 now so it's not really beating on trans

Why not swap fuel injection then put a Holley stealth ram stalled cam would be a healthy setup

 

http://www.vettefacts.com/C4/1985.aspx

Search before you buy people some times don't know what they have and others try to rip you off

 

the prob is it is a pick and pull motor do I will have to research the vin... the car was recently damaged on the drivers rear so motor should be fine headed to pull it now...I'mplanning on the xe268 can and minor port job for this I'm pretty sure tbi could run out but if I were to put it in how much of a pain would it be to time?

 

I would keep TBI and upgrade the ECM with the EBL flash, it is a simple set up and works wery well.
IIRC the zz4 engine produces around 340 hp on an engine dyno, I have the impression the corvette L98 engine with the cam you mentioned will make less hp.
Have you played around with some engine simulators? that will help to decide if it is worth upgrading the intake manifold and will be a ok indicator for fuel requirement too.

 

Ill say 220ish to the rear wheel

 

What flow numbers did u use?

FWIW Desktop Dyno 5 shows

rwhp @ rpm with standard-flow dual-plane
245......4000
252......4500
246......5000
219......5500

rwhp @ rpm with high-flow dual-plane
257......4000
272......4500
269......5000
238......5500

rwhp @ rpm with max-flow dual-plane
264......4000
280......4500
282......5000
243......5500
202......6000

 

consevertive guesstimating which i was pretty close ..220ish depending on intake of choice yes its low but like i said its a consevertive guess i was think more 240ish depending on Mods.. but OP never stated what carb or exact intake that was in use or how did he work on the tbi did we just grind down lip or was it fully ported etc and didnt state what cam he is using so im basing everything off stock l98

cant rely soley on desktop dyno those numbers are created when the conditions are perfect controled setting and as long its a information put in is correct

but looks like numbers are falling off after 5000 so i assume they have about the same charteristics as a tpi intake

i have played with desktop dyno and i really dont bother with it

c4 dyno run

theres to many variables to rely soley on desktop dyno IMO

 

Gotcha, O.P. wrote "I'mplanning on the xe268", that is why I was wondering how you came up with 220 rwhp.

The 5000rpm seems to be the top of the power band of the cam and heads configuration, the sigle plane intakes did not show any improvement over the max-flow dual plane.
The only advantage of the TBI vs TPI, would be the lack of the Tuned Runners.

I have also the earlier Desktop Dyno Simulators and I agree that the numbers are not wery realistic.

 

lol

yea i was actualy close to your numbers but i like to guess low and be happy that it dyno higher then guess high and be disappointed on dyno low

but i agree numbers do look about close for the setup its a good starting point

and i agree tbi would be easier to swap and more intake choices

it would be intresting to see a different cam an tbi on a carb intake prob dual plane 1800 to 6000rpm range pulling hard to 6000 that would be a cool combo

i wish i still had my tbi to mess with

i have earlier version too its fun to mess with tho

 

okay so i started the engine teardown today and instantly realized that someone has had this engine apart before, as of now it looks like only from the manifold up were off. the intake amnifold is sloghtly ported at the point where the runners attach and from what i can understand the manifold is from a later tpi motor because the two center manifold holes are slightly opened to accomodate the different years bolt angles? any ideas? oh and i thought the top tpi snorkel was supposed to have some sort of walls or ridges in it to direct airflow to the runners but this one is completely hollow inside... also do the lt1 throttleboddies fit the tpi intakes because this lookes too nice and a little different than the ones i have previously seen...

 

where you at you working on it right now im off today

 

FML so it turns out the owner of the vette that i pulled the motor from was a cheap SOB and must have blown his stock motor or let the car sit so long it siezed because he went the cheap route and bought a 14093638 block and put his tpi crap on it, god only knows how long he had that in there...oh yeah and just my luck, he bought a 2 bolt main block...so i definately need to junk the 193 heads and possibly the entire block too... the rods, pistons, crank, and oiling and cooling ports are in fantastic shape... there are even hone marks still on the cylinder walls with very very little fine scuffs from rings it would be a shame to scrap this block...any ideas?

 

2 bolt good up to 550ish i wont rev past 6000
2 bolt is good for a street car

of course 4 bolt is stronger

its all in what you want to do and goals
but base off what you talk about and hp goals you should be fine

i would run it with some cheap vortec heads and a matching cam for your combo
keep in mind depending on cam you might have to throw a higher stall which you will enjoy more

 

http://www.jegs.com/i/Edelbrock/350/7116/10002/-1
as stated by your cam choice xe268 would be good

but

i think stepping up 280xfi hr13 with cheap vortec heads for around 300-400 with a stall (your engine is out and would be a easy upgrade to do ) and upgraded gear when you swap to 4th gen rear and using headers and upgrded exhuast system
and using this intake
http://www.jegs.com/i/Edelbrock/350/7116/10002/-1

http://www.compperformancegroupstore...ode=RLERCAMXFI

you can mill the heads to incerease CR since pistons have slight dish and valve reliefs and as long you PTV checks out

would be more satisfying and wouldnt hurt the bank to much

 

Hey my3rd, I saw that car last week at ecology. I got the valve covers and was looking for a set of l98 heads. I saw the 193 heads and 638 block and left it there. That's the same junk I have sitting at home now. Best of luck with your build !

 

its fine, i am looking for some heads and i am just gonna buld it with a cam, good heads and performer intake then mount the tbi on it put a chip in and have some fun with it until i build a 010 block something?... good motor setup to run on an all stock drivetrain for now i guess maybe shoot for 370 chp for now then 600 later

 

good luck with project post pics

 

'638 was the ( only ) factory fitted block for a late Vette L98 (w/ alum heads ) and all L98 Vette engines were only 2 bolt.
If you had a 4 bolt '638 block it would have came out of a truck

4 bolt mains weren't in a C4 Vette until the LT1

 

^^What he said^^