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Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
Picked up this yesterday. 70k mi, PO said it ran strong w/ no smoke. Said he believed it to have some package on it that included headers, upgraded fuel injection parts, and cam? What I can see is the siamesed runners and slp headers which were in rough shape banged up from swap I suppose. Engine was swapped out for a newer model Corvette LS. My plans are to refreshen it, find out what cam is in there and if I want it or not, and put an upgraded TBI system on it and into my red bird.
It may also get a set of Vortecs depending on what these heads look like. May be spring before I get to it. Very excited I'm not building a race car just something hopefully 75-100hp over my lil 305.
It's an 87 engine. Judging from the oil cooler, it should be a good 'un. I'd rip the smog pump crap off, and sell the one year only accessory drive setup, bolt on the serp setup from your TBI engine, and convert the TBI harness to work with TPI. It's too easy to convert a TBI car, and it'd be a nice swift kick in the *** of performance just the way it is. 70K she ain't even broke in yet!
Id love to swap to TPI but that may be too much of a headache for me. Then again I would love that setup I just don't know if I have the patience or time. Nothing looks cooler to me than that setup under a hood for sure. I will probably end up selling the TPI setup, I already have another 87 setup in a box somewhere from my last TA but its doesn't have siamesed runners.
Swapping in that TPI would be easy. Change the pump in the tank, the rest of the fuel lines are the same all the way to the fuel lines on the engine. You'd need the two stubby lines and bracket from a serpentine car. Cap and plug the CSI. Wire it up as an 89 MAF or 7730 MAP. Swing the battery to the driver's side and wire it up. Hardest part is probably finding the PROM, the rest is really just a matter of labor.
Tooooooned Port. Tooooooned Port. It just rolls of the tongue.
Swapping in that TPI would be easy. Change the pump in the tank, the rest of the fuel lines are the same all the way to the fuel lines on the engine. You'd need the two stubby lines and bracket from a serpentine car. Cap and plug the CSI. Wire it up as an 89 MAF or 7730 MAP. Swing the battery to the driver's side and wire it up. Hardest part is probably finding the PROM, the rest is really just a matter of labor.
Tooooooned Port. Tooooooned Port. It just rolls of the tongue.
While it does look cool.. the most I ever fought a car was with a TPI and I eventually jerked it out and went carb. So far I haven't had to touch the TBI. It has been incredibly reliable, trouble-free, and underwhelming as well. Lol
I would go for the aftermarket TBI set up form Holley msd FIT etc they are getting much cheaper now and you can run any 4 barrel intake with them and air cleaner prime low hassle set up for a SBC .
While it does look cool.. the most I ever fought a car was with a TPI
Was it MAF? Because my Iroc drove me crazy, while my Formula has run beautiful with all kinds of self inflicted issues that should have kept it from driving.
Bought a new engine stand and got her perched up there. Also got some new torx bits and started removing some things last night. But mainly just drank beer and looked at it. Lol. 95deg here now and after working 12hr days I'm not feeling like doing too much at this point. Just a lil at a time. I'm very excited though and going back in forth in my head whether to leave the 083s alone or go with some Vortecs like my last build.
Does anyone know the specs on the SLP cam or cams the dealerships put in the SLP packages back in the day. I don't know for sure because I haven't pulled it yet but "supposedely" this engine has one. It did have a lil bark to it so hopefully I can find out some specs and I don't have to discard the mystery cam. I do have a low mileage 049 GM cam I thought about using if it comes down to it. I'm not wanting a drag car just a strong cruiser. Something to maybe discourage pickup trucks and minivans from embarrassing me anyhow.
Got the TPI off today. Engine looks very clean. Was too tired and greasy to take any pics. I'm ready to find out what cam is in there. Don't know how much more progress i will make for a while I go tomorrow to see what they are going to do with my fractured hip. It's been nagging me awhile i need get my hip rebuilt first. Then the L98.
Get out the dial indicator and magnetic base, and measure the lift. I'm sure someone has an old Summit catalog or SLP catalog with their cam specs. I probably have them somewhere... Might be easier to pull the cam gear and look for a number on the cam snout.
So, I'm going to run TBI on this engine and put in a stock TPI GM#049 cam. Should I bore the TBI and intake to 50mm or would the stocker with its 42mm bore maybe with ultimate tbimods be ok for this engine? Would 50mm be overkill i guess is my question?
Those runners cleaned up well Bob. Hopefully I can get off these crutches soon and start fooling with my engine. Can't even put my dang shoe on by myself at this point so getting Zero done here for now.
Wanted to stay with the stock TBI intake so a friend of mine here on these boards did some excellent work boring this one out for me and making it look great. Thanks Robert
Ive also been doing some work on this one and neglecting the Pontiac lately as my sons studies for his driving permit in January this will be his birthday present.
What did you guys use to clean, strip, blast, paint, coat, etc. etc. those parts. Both the runners and plenum, TPI manifold and the TBI manifold all look great. I've found several different paints and coatings that look great, but that brand new cast appearance has eluded me thus far!
I followed Bob’s advice and used the Eagle One etching cleaner on my SLP runners, Big Mouth and plenum. Man, that stuff is strong! Followed it up with Duplicolor Cast Coat Aluminum DE1650 and I’m very pleased. Will get some pics once I finish with the brown truck.
Stock 083 Heads reworked. 46mm TBI on the way. Engine looks good going to hone it, re-ring and re-seal and new bearings, freeze plugs etc. Going with stock GM #049 TPI cam. 207- 213 .415 .431 On the fence to use TPI manifolds and magnaflow y-pipe or Hooker headers + y-pipe. This is a mild build I know but this should be a nice jump in performance to go along with my already upgraded tranny, torque converter, and 373 posi rear. Car is mainly for cruise-ins and Sunday evening drives not a racecar but a fun car
Took the 70k mi L98 engine down today and everything looks great. Parts soaking in the parts cleaner tub tonight. In next few days it will be out back together with new rings, bearings , seals, cam swap, etc. Heads are reworked with new springs, retainers, seals, etc and hopefully this swap happens soon. Been needing to get this done a few years. Tomorrow I will post a few pics and try to figure out what cam was swapped in there- i may sell it. I think it's a 268 comp cam. I'm going back with a stock #049 GM cam
I will sell this cam that I pulled if anyone interested and will throw in the matching comp cam valve springs $125+ shipping. If it don't sell It may go in the 305 im fixing to pull out in the next few weeks. Thinking a square body S10 with the cammed 305 and maybe some 059 Vortecs would be a fun street build.
While honing the last cylinder noticed some pitting and have decided to go on and have the engine bored 30 over. Ordered new flat top 4v relief pistons + rings today so another short delay. No machine shops local anymore so will have to travel over an hr hopefully next so if my pistons come in. I will not go through another engine again- crate engines save you money and time in the long run I've come to realize.
Month later and block is still in the machine shop. Have a chip tuned for the L98 with stock #049 cam. 207-213 .415 .431 lift IIRC but am really thinking of going with the 66492 GM cam 214-220- 465? lift. I wonder would the tune be far off since its not a huge jump in the cam. My heads should be good for .475 lift with the new Z28 springs according to my guy that redone my heads so im good there. Have a 46mm TBI with 15lb spring so I will be borderline on fuel but I think ok as long as my pump will make close to 14-15 psi
My Dad and my son have about got it put back together and we will maybe be getting her over in the car in the next 2 wks. I can tell my Dad and and his Grandson have been very excited about doing this together sucks ive been out working til dark 30 every day I haven't got to help a bit.
All finished up and heading over to a friend's shop to start installing this week. Wound up boring .30 over, 4v relief Mahle flat top pistons, GM #049 cam. Basicly stock L98 rebuild. Going with a bored 46mm GM TBI unit built by SPR Motorsports with intake to match. Hooker headers and 3in exhaust. Already an S10 TC and 3.73 PosI In place so that will go over well.
Heck yeah! ......looking forward to your thoughts on it when done!
It will still be slow but much better than the L03 im sure. I may have left the L03 alone had it not began to smoke a bit. I really just want a good strong cruiser and I didn't want to put a 305 back in a car. Been there and done that before. I am curious how this engine will do on an upgraded TBI instead of TPI. Im running a 46mm unit with bumped up fuel pressure and intake bored to match. Only other mods are better chip tune,full exhaust of course, 3.73s, and S10 TC.
I've never seen dyno results of any sort but I personally felt my car was a bit quicker after swapping to tpi. Was that due to tune? Possibly. On paper a modded tbi isn't a terrible restriction though it could use a couple more throttle blades. How does that compare to the rpm restrictions of a tpi? It would be interesting to see.
Yeah I honestly don't think it will make the power it would with the TPI on top. This engine was specifically designed for TPI but then again Ive seen folks throw nothing more than a carb and decent inake on TPI 350s back in the day and hit 13s so it wasn't completely optimal was it. Mini-Rams made much more power I always thought.Ive just always been curious how much difference the TBI would be on the same engine. I know L03s and LB9s are worlds of difference in power seemed like but you had cam and exhaust restriction there also.
Coming along. Hopefully another 2wks or so she will have a new attitude. Right now night work/ 7 days a week it's been hard for me to do too much at once
05-17-2018, 07:37 AM
