88 vette L-98 planning 383 stroker. Need advise

  
Item Posts    Sort Order

88 vette L-98 planning 383 stroker. Need advise

 
Cleelopez Cleelopez
I watched Corvette Summer | Posts: 6 | Joined: 01/11
Posted: 01/15/13
08:28 PM

Hello All!
I have an 88 l-98 automatic. I'm seriously considering a stoker build. I have spoken to reputable builder in town. He couldn't answer some of my questions. Says he needs to do some research. My goal is a min of 450@fly. This is a weekend driver. No track use or intentions. I want to use the stock ingnition system,intake,runners,plenum and TBI. But having the goal in mind I know the stock heads must go. Going with a set of AFR aluminum heads. Will the stock base intake and runners be sufficient for my goal? I haven't desided on the cam profile yet. Hydraulic roller most likely. I've searched around the Internet but its hard to trust or get solid answers. Is upgrading to edelbrock intake base and runner worth it? Do I  upgrade the TBI?  Will I need larger injectors? Shorty headers? Is stock fuel pump good enough?i have a 700R4SS from monster transmission rated for 650hp. Better safe than sorry.  Inhave the taladaga top so how do i go about stiffening up the chassi right? I know its a balancing act but what combos work? Will the stock cooling system be alright? I'm going about this cautiously and want to do it right the first time. I truly love this car and have it garage kept and in tip top shape. Please everyone. I will be grateful for any information I can get. Thx  

pepsi1 pepsi1
Duntov Incarnate | Posts: 88 | Joined: 01/12
Posted: 01/16/13
01:14 AM

Cleelopez
Lets take one thing at a time.
1.Making 450-500Horse Power is not a problem with a Small block Chevy.
B.A.450-500 streetable horse power your on the verge of it becoming a hand full.
C.Stock ignition yes maybe recurve it.That still would be a question?
D.Maybe on the stock plenum, The TBI?, larger injectors, bigger fuel pump,and regulator, More horse power more fuel.
E.Aftermarket Heads yes intake runner/cc will depend on the cam.
F.Headers a must long tube to get the benefit of all the HiPo upgrades.
G.You will need a 3500 to 3800 Stall Convertor for the trans. the Big/Ass trans you will need........
H.You will need a stout Hydraulic Roller.
I.You will need to upgrade the ECM.
J.Your rear gear 3:90-4:10 depending on how tall your tire is....26"-28" is good.If taller then 30" 4:30+ rear gears.
K.Plus machine Shop Labor.....
L.Not done just going to do some research. See next post.

Bob  

pepsi1 pepsi1
Duntov Incarnate | Posts: 88 | Joined: 01/12
Posted: 01/16/13
01:57 AM

You know your in for a big job....With that said.
I looked for an engine from GM and Edelbrock,and Jegs. They have no engines 383 with a TBI injection.

Jegs has a 350/350 Ram Jet thats complete for $5,600. Its a GM engine. It has all the good pieces. I know thats not what you want.

They have carburetor versions up to 420 HP and 450lB.fT.TQ. $4,600 plus dress-up kits..ETC.

I know for a fact unless someone installed a Good HiPo Block in your 1988 Corvette you will be surprised to find out it doesn't have good parts to start with. Just taking it and installing a 383 crank kit with all forged parts you can get up in the 450 HP range without a problem.

FYI: My advice is to buy a good short block with all the good forged parts. Then build your engine from there. Heads, Cam, Injectors, ECM upgrade, Long tube headers. Then work with those parts, and make the modifacations you need to get the 450-500 HP. It may not be all that hard to do.It can be done. Just get a good foundation. Smile

As far as the chassis stiffening They do make reinforcement chassis parts. (I've seen those roofs leave the Corvettes) Not pretty at all!!! Grin  Cool

Bob  

pepsi1 pepsi1
Duntov Incarnate | Posts: 88 | Joined: 01/12
Posted: 01/16/13
02:14 AM

I did get to run my kid brother's 2002 Z06 at 174 MPH at Daytona, in a car club he was in. He still studder's that was 10 years ago...Only kidding.

There was a Video with the Z06 on how to set them up for the track. We ran passed other Z06's these guys didn't want to take the time to make the changes they needed..They are made to race....

Bob  

lonewolf11 lonewolf11
Duntov Incarnate | Posts: 105 | Joined: 04/09
Posted: 01/16/13
10:51 AM

Cleelopez, Pepsi1 is correct in so many ways. He has steered me in the right direction more than once. I have a 1987 and 1 1/2 years ago I found a crack in my L98 block between 6 & 8 pistons. Long story short I found another Corvette guy who had built an engine, Gen1 Block 350, with everything new from the Oil Pan on up to the Carb. I bought the motor minus the top end, Intake & Carb, and used my TPI from the L98. With Flat Top Racing Pistons with 10.5:1 compression up from the stock 9.5:1, a HEFTY CompCam (non-computer controlled btw) and everything pointing to a hella strong motor. I had my L98 heads redone, cleaned & installed 1.6 Stainless Roller Rocker's with all new springs etc. I did have the Plenum & Runner's cleaned & honed to creat smoother surfaces. But the runner's & Plenum aren't really up to the task as neither are the heads. I should have gone AFR heads, LARGER runner's & plenum. Many are out there to compare which is best for your application. I will suggest going with a larger BBK Throttle Body as well, either 52 or 58mm. If I would have had the money at the time I would have gone the way of F.A.S.T. intake vs the factory setup of TPI, which isn't up to the extra horses you want to corral. I have a set of Shorty Header's I had built some 6 yrs ago. Long Tube is the way to go & then have the rest of your exhaust system to match with the upgrades. Chassis strengthening can be found in a Cross member you can find at Corvette Central (roughly $300 I believe). You may think about a brace to go across the backs of the seats as well. Kinda like a roll bar but stiffens up the body as well. Unless you relish the idea of changing the Fuel Pump in the gas tank I would stay with what works in upgrading the engine & staying within the Fuel Pump range. Which as far as I know will work & still get you in the HP range you seek. My last advice, be careful with what you do. After my install I have spent the past 1 1/2 yrs correcting or upgrading or at the very least replacing what I had done with what actually works. Time & Money were not & are not my allies in my own project but I have gone dowmn this path and must deal with it. Good luck in your project & if you need some of my experience of what NOT to do, write.  
Gregorio Lonewolf

lonewolf11 lonewolf11
Duntov Incarnate | Posts: 105 | Joined: 04/09
Posted: 01/16/13
11:13 AM

May I add here that going with a Crate motor, most are of the Carb variety but you can get them without this setup, and go the way of after market Fuel Injection Intake if FI is your goal. Had I been more thoughtful in my own motor replacement I would have done so with a Crate Motor. I really like the idea of Summit Racings BluePrint Engines. My own choice, if I was thinking, is the 355 ci, 375 hp, 400 ft.-lbs., 10:1, part # MLL-BP35512CT. They also offer 1 that is a 383 Stroker @ 405 hp, 440 ft.-lbs. As well as 1 closer to your numbers of 420 hp, 450 ft.-lbs w/10:1 (part # MLL-BP3834CT1). All you need to do is the type of intake you wish to install. BTW, all are under 4g's. Which after my costs is much less than what I finally have & am paying for. I have headache issue's I am addressing with my own build and finally am at the end of my problems but it has cost me. Some things you may wish to think about with your project. Again, good luck & do plenty of research as I have. My own experience has gained me much knowledge but not for lack of the stress I have endured. I just noticed your question about injector's, yes you may need to upgrade if yours are stock. You can contact me at this site if you wish to get the addresses of those who helped me, including reprogramming my ECM as I have made many changes, including 160 Degree Thermostat, which the ECM was reprogramed for. Cost was within my dustbunny lined pockets.  
Gregorio Lonewolf

Cleelopez Cleelopez
I watched Corvette Summer | Posts: 6 | Joined: 01/11
Posted: 01/17/13
04:56 PM

Hey guys.
I want to thank you all for the great advise and look into my road ahead. I will definitely speak more with my engine builder about my new found knowledge. At this point in the game I can't go crate. I had him build me a496 stroker for my camaro that dynoed out 560hp and 640ftlb. Then the economy crapped and I was down to 30hrs a week. So my project was scrapped and I gave back the Bb in exchange for a SB build when things picked back up.. I will definitely post in the future as things progress and a solid combo has been established and will post specs and parts upgrades ect and see what you all think. I have a sound tuner that did my other camaro lt-1,rebuilt 355,cam,exhaust upgrades. After 4 bad tuners and a bad experience with a mail order tune this guy reeled it in nicely. Thank you all very much and hope to hear from you again ! Happy new year and god bless.  

Cleelopez Cleelopez
I watched Corvette Summer | Posts: 6 | Joined: 01/11
Posted: 01/26/13
08:01 PM

Thanks. I've been going back and fourth in my mind as to my combo. I don't have a large budget. It would be easier to ht my numbers if I go with a carb. But that brings me to other questions now. How do I go about proper fuel pressure. I believe the stock pump maintains 43lb of pressure and carb needs 5-6 lb. do I disarm and install 65gph 7 lb electric inline fuel pump with pressure regulator? Or go mechanical?  How about the stock distributor.can I use it? Isn't the rpm digital gauge run off the distributor?  And would assume the advance on it is electronic or vacuum? How about the speedo? It's gonna cost some good bucks to tpi upgraded enough for my numbers but going carb seems easier but may cost me how much? You've gone  threw the pains of the build..  Please lay some wisdom on me.  

waynep71222 waynep71222
Duntov Incarnate | Posts: 241 | Joined: 04/12
Posted: 01/27/13
07:10 AM

its only about 30 minutes work... to change out the intank electric fuel pump... right through the top deck... yep.. it all comes out.. be sure to order a DELCO G-1 gasket... so you are ready..

you have several ways to ***

you can run the stock high pressure pump with a special HIGH PRESSURE fuel pressure regulator.. so you don't overcome the regulator control... as most may not handle the probably 75 PSI that pump can create... you will also NOT want a deadheaded fuel pressure regulator.. you want a BYPASS type of fuel pressure regulator...

why... none of the intank fuel pumps have a bypass valve ..  if you dead head them the CURRENT DRAW increases significantly... overworking the power and ground circuit to the pump... burning the fuel pump relay and the oil pressure switch contacts that control the fuel pump power delivery..

depending on what you find...   you can also install a fuel pump from an 84 crossfire model.. it tops out at around 25 psi.. a much more manageable pressure..  check the pressures at the AZ site in the detail...

there are also 6 or 7 PSI pumps that will bolt right in.. but will they deliver enough fuel through the small fuel lines to keep you from leaning out the motor...

the stock high pressure pump with a QUALITY bypassing fuel pressure regulator is probably the best way...

have you examined the catalog from TPI Specialties... or some of the other TPI fuel injection components suppliers...

even switching to a GM ram  port fuel injection manifold if it will fit under the hood..  i think edelbrock also sells something like that.. and possibly keep your ecm ... this might be possible i have NOT studied it..  these years of GM ECMs have a LOT of aftermarket support... so tunes are available on a chip..  

don't forget...    that if you seriously increase the engine horsepower.. you are going to need to spend a serious chunk of money on the 700R4 to make it live behind the new motor...  this allows you to drive it without hopefully ripping the transmission up and leaving you stranded.
don't forget to plan for an additional or a stand alone large transmission cooler...

lastly... before you go to a carb... and plan on tossing the fuel injection all the way out..

some of the data stream to the instrument cluster comes from the engine control computer..

the computer also controls the radiator cooling fans... to keep the engine from overheating.. its not hard to revert to automatic electric cooling fan control..   you really don't want the fan/s running full time.. the fan motors were NOT designed for that extended duty cycle.. the shafts build up heat and melt the middle of the fan blade out... allowing your pride and joy to overheat..

i am NOT trying to talk you out of what you are planning.. as it sounds like a LOT of fun... i just want to make sure it is fun.... forward thinking.. unlike what was joked about with cars like the yugo... where the last models had heated rear windows to avoid freezing your hands when pushing them down the road..  

waynep71222 waynep71222
Duntov Incarnate | Posts: 241 | Joined: 04/12
Posted: 01/27/13
07:41 AM

lastly.. what ever you *** if you have an automatic...  understand that the throttle valve cable from the throttle body or the carb to the transmission adjustment is critical... get it wrong your nice new transmission will last about one lap around the block..

most carbs also require an adaptor for the bottom of the lever to get the proper ratio...

the distance from the center of the shaft for the TH350 design most carbs come with is slightly greater than the distance needed for the 700R4...   its about 10 bucks in parts to fix this..  


what .. why....   with the longer throw of the standard carb lever..  if you get the TV Cable idle adjustment correct..   at WOT.. the extended lever length will max out the cable movement and pull the casing out of adjustment..  so when you return to idle... the adjustment will be too loose by about 1/4 inch... reducing transmission line pressure to the point the clutches slip..  

Cleelopez Cleelopez
I watched Corvette Summer | Posts: 6 | Joined: 01/11
Posted: 01/27/13
08:53 AM

Great info. The ECM. I was aware of the involvement of most functions but to what extent is unclear to me. I am hoping to keep it in use but at a minimal capacity to control the cooling fans,rpm cluster if possible. Still trying to weed out the electrical. I will definitely keep the wiring harness intact cause down the road I may switch back to EFI just I case I'm not happy with my set up.
 I do have a 700R4SS from monster trans thats rated for 650hp/600lbsT. with external lock up and the adjustable TV cable and trans cooler kit and complete synthetic fluids with a 2600/2700 stall. So I should be ok on that end.
GM efi intake? Which were you referring to? And hood clearance has been one of my issues. I found a strealth ram intake on eBay for a killer price and under notes said wont clear corvette hoods! I said,"damn it man!" The edelbrock base and runners was another thought but for only a 20hp gain with a 900$ price tag? And the super rod mag results were done with 36lb injectors,seperate tuning management ecu and electric water pump. No accessories or drive belt system so I don't know how much hp would be lost there. I've had the engine build on hold trying to sort out and map the way. The devil is in the details and I'm trying not to get my ass handed to me by rushing in. But it's a bit nerve racking and once I commit there's no going back.  

Cleelopez Cleelopez
I watched Corvette Summer | Posts: 6 | Joined: 01/11
Posted: 01/27/13
11:25 AM

The GM ran jet is what you were talking about? Please can anyone clarify something. What are vortec heads. I notice a lot of these intakes are for use with them. I intend on using AFR 195CC heads on my 383. With these systems say aftermarket ecu required? Why? Can't the stock ecu chip be programmed to run my set up?  And the kit is Speed density metering? What is this? No mAF? I hope no one thinks I'm dumb for asking but I figure it this way,the only dumb question is the one you were afraid to ask?  

Cleelopez Cleelopez
I watched Corvette Summer | Posts: 6 | Joined: 01/11
Posted: 01/27/13
06:59 PM

Ok guys. Here's what Combo I am considering. 383 with eagle stoker and assembly. AFR 190/195cc heads undecided. Comps XR284HR/XR288HR undecided . Edelbrock Rpm air gap provided I have hood clearance with Holley 750 carb. MSD distributor. HookerComp 1-3/4 long tube headers w/3" exhaust. No EGR components,cats. Full accessory drive with a/c and pump delete.
Based on the research it should fall in the 475hp ball park. Very similar combos landed around 460-500hp. I'm have stock 255 50 R16 tires. May go a bit wider. The stock Dana 36 w/2.59 which I will jump up some. Maybe 3.07/3.31 it's not a track car. I've heard conflicting info on the Dana 36 but as far as I'm thinking I will have a hard enough time keeping the tires hooked up so I'm banking on the tires breaking loose before I can damage the Dana36. But am a bit worried about the u joints. Any thoughts???  

pepsi1 pepsi1
Duntov Incarnate | Posts: 88 | Joined: 01/12
Posted: 01/29/13
01:24 PM

The Vortec is a way the fuel and air is mixed in the head before getting into the combustion chamber. Then in the swirling mix it explodes on the power stroke making more power. (Thats the simple version). But the Vortec head has it's limitations.

You can only use a cam up to .450 lift. Then the valve guides need to be cut for retainer clearance, then the valve pockets need to be made wider.

Bob  

Testiculese Testiculese
I watched Corvette Summer | Posts: 1 | Joined: 03/13
Posted: 03/06/13
10:08 AM

You said no track use just a weekend driver. I suspect this is because everyone with a mustang Camaro or dodge whatever comes out of their mobile home on the weekends looking to race a Vette.  Think of your engine as a big air pump. the more you can get in and out the more power you can make in theory. Intake-- take a look at  "First Fuel Injection" they have a TPI set up that was tested by some people at 3rd gen and it pulled 301 cfm out of the worst runner. Do you really need a 383? yeah it a little more torque but remember why 383 are popular. Way back when 20-25 years ago, people would take a 400 crank and machine it to fit a 350 block for 1 reason....to cheat, to pass it off as a 350 at the track. Now its too well known to cheat. The torque isn't that much more.
What you seem to want is that throw you back in the seat butt clenching feeling of GForce and the ability to smoke these newer non Vette driving mouthbreathers. That's Torque, not HP, HP is for top end, Torque is for lifting the front wheels off the ground when you stomp it. What rear end ratio are you running? Last year I got another Vette that I couldn't pass up. 1991 TPI L-98 with 30k miles original everything owner was in dire financial straights and said 6 cash and it was mine...lol...I think I about blew up my other Vette racing to the bank to get the cash. I'm rambling....anyways this nice new/old vette had 2.59 ratio gears in the rear end, I switch the pinion and ring with 3.54 ratio gears and it was like night and day, Imagine going from riding in a 4 banger to any strong V8 that's what it felt like. Even with the 2.59 gears the car was decent but after changing its gears and a few other things acceleration from a dead stop to 100 can almost be called violent, or vulgar. It actually scares some people that aren't use to being pinned to the seat so hard.
What did I do?
2.59--->to 3.54 rear end
AFR 195 heads
First Fuel Injection intake manifold
Camber brace....get this so you can keep alignment geometry on hard corning
X brace and interior brace behind the seat....to prevent body twist.
219 cam
315 wheels from a C4 ZR-1 in the back
No I haven't touched the tranny, I figure when it goes I'll get a high speed aftermarket unit.
I have a buddy with a C6 he use to blow my doors off with my old 86TPI, with the 91TPI he did the same when I 1st brought it home. Now I utterly destroy him off the line and gradually make more and more room between us as we go down the road....up to about 100 I don't like driving faster than that as I like having a license. That's a gen1 SBC vs. an LS.
The biggest noticeable (feelable) add-on I did was the gear swap in the rear end. Remember a nice rear end makes everyone happy.
Decide if what you want is Torque or HP. HP sells cars and makes those nice 190mph claims possible, but Torque makes their front wheels come off the ground and really how often do you ever really need that super high top end speed?
I can't wait till the summer. Gonna throw a procharger on it and see what happens.