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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.
Trying to figure out why the flexplate on my Vortec crate 350 isn't lining up with the bolt holes on the torque converter. Do I have the wrong flex plate on for my 83 Z28 tranny?
What's the easiest solution or do I need to drop the tranny and swap the flex plate out? There appears to be 1/4" gap between the flexplate and converter as well, is that too much a gap?
Maybe I should tackle the T5 swap I want to do and move on....
Thanks all
I found thi
s info: GM made a 168 tooth 11.50" flexplate #12554824 and a 168 dual 10.75" / 11.50" pattern flexplate #14088761
Now I can't say for sure, but is there another set of holes in your flexplate for the smaller diameter pattern?
As far as that gap goes, is that with the converter all the way into the transmission? For operating, it should be pulled out towards the flexplate by about the thickness of 2 flat washers, which is what your picture shows.
i think you need the later model flex plate(for 1 pc rms),i also noticed the vortec crank takes larger bolts than the third gen engines for some reason.
i bought a flywheel (t5 )and arp bolts(for a 2nd revision sbc -1 pc rear main seal ) for a vortec swap and needed to use the bolts from the vortec
flex plate(they are larger,maybe because of being truck use? don't quote me,just an idea..
I have the later model flex plate, this is a Vortec truck engine (1996-1999) model years with 1pc rear main seal. I'm pissed at myself for not thinking of this while the engine was out.I don't see holes for the smaller diameter holes...bummer.
So, I read where someone suggested, after removing the bellhousing bolts, to swap in some 6" bolts to hold it in place, slide the tranny back, while I remove the flexplate without having to fully remove the tranny. Essentially just sliding the tranny back 6 " (obviously remove the driveshaft and torque arm) in place to give me room to swap it out.
Is it easier to unbolt the torque arm from the rear end and pull it out of the tranny?
if you have the vortec flex plate it may not be drilled and tapped for the third gen torque convertor,it also will be the 168
tooth instead of the 153 tooth(i think) and you would have starter issues as well(if its the larger flex plate)
ive got a vortec truck engine too just pulled out of this truck,look how god level clean this baby is.truck now has a 383,that was the only reason the motor was pulled.
here it is on the stand,im waiting to pick up some comp cams retainers so i can put my new cam and beehive ls6 springs in.it will be virtually identical to the sp350/357 horse crate engine with the cam i have.(i pity my poor t5-might have to go automatic if i cant find a good t56-tko under $3000)i have a nice holley ultra 650 double pumper-mech secondary,not using this edlebrock carb junk.this is the cam i picked up.perfect for a set of beehive ls springs.
also just scored a set of ceramic coated hooker headers(mid length)they are on my L98 right now but im putting them on this engine.
everything ive got so far has been used(other than the flywheel),the cam was pulled out of a crate engine because the old fella said it
was to lumpy(perfect for me,thanks)i dont know how anyone can buy everything new,my family would starve and we would be homeless,lol.
Last edited by 1986BANDIT; Aug 13, 2019 at 08:25 PM.
if you have the vortec flex plate it may not be drilled and tapped for the third gen torque convertor,it also will be the 168
tooth instead of the 153 tooth(i think) and you would have starter issues as well(if its the larger flex plate)
Yup. Like he said. You need an F-body flexplate. Lot of vortec swaps going on I see. Great swap and lots of room for upgrades in the future. Next is LS.
did you cam this or is it a stock L31 crate? easy upgrade ,just the sp350/357 cam (P/N 12677151) brings it up from 255 horse to 357......
bumps the torque to 410 ft lbs and you don't need to do any machining for springs,just LS1-LS6 Springs and comp cams
retainers as long as you stay under 0.550 lift(aprx) i wish my engine was factory fresh too,oh well i guess that's why it
was $700 and not 3-5 grand.its surprising how little they do to the sp350/357 crate engine,just add cam,sell for double $$$$
im not going to bother with the LS until absolutely necessary,i see little need as 360 horsepower and 410 ft lbs is plenty
Last edited by 1986BANDIT; Aug 14, 2019 at 04:07 PM.
did you cam this or is it a stock L31 crate? easy upgrade ,just the sp350/357 cam (P/N 12677151) brings it up from 255 horse to 357......
bumps the torque to 410 ft lbs and you don't need to do any machining for springs,just LS1-LS6 Springs and comp cams
retainers as long as you stay under 0.550 lift(aprx) i wish my engine was factory fresh too,oh well i guess that's why it
was $700 and not 3-5 grand.its surprising how little they do to the sp350/357 crate engine,just add cam,sell for double $$$$
im not going to bother with the LS until absolutely necessary,i see little need as 360 horsepower and 410 ft lbs is plenty
Stock L31 . I was gonna swap the cam out but was still learning about the vortec head restrictions, cam combos without machine work etc, so I decided to run the stock cam for now till I feel I need more power. And now I do feel I need more power lol. Gonna be tackling a cam job in a few months. Regret not doing it from the get go. But hey, still plenty of power to mess around or roast some tires. Gonna look into that cam. So your doing this exact swap? Are you gonna dyno it? Would love to see the results.
Last edited by maroe624; Aug 14, 2019 at 04:39 PM.
that's a shame,its so easy to do out of the car and you would've got an easy 100+ horsepower using either stock springs or ls6 springs($60-$70 at summit) and the comp retainers.other guys go with the LT4 but i got this 7151 for $200 so that's what im going with!! so,zero machine work.swap and go!!!! im just putting the engine together now,i bought it used so im doing gaskets,bearings,timing chain etc.i can only do as much as i can afford ,a little bit at a time.
basically the gmpp crate engine SP350/357 is just a stock L31 vortec with the 7151 cam.you will make 360 horse and 410 foot pounds at the crank if you use this cam (P/N 12677151) and your L31 vortec
Last edited by 1986BANDIT; Aug 14, 2019 at 04:43 PM.
headers and exhaust make a difference too. I went with Dyno Don's, large primaries down into a 3: exhaust. Most headers are too restrictive on a 350.
My L31 is stock too for now. I do have an air carb gap intake on top.
I bought an 83 Z28, red with t-tops from Arizona. No rust! I live in New England and most are rust buckets...
I need to swap my flexplate out to lineup and will be good to go. cracked into it tonight, placing an Amazon order to get the flywheel for this week, 2 day prime shipping baby!
that's a shame,its so easy to do out of the car and you would've got an easy 100+ horsepower using either stock springs or ls6 springs($60-$70 at summit) and the comp retainers.other guys go with the LT4 but i got this 7151 for $200 so that's what im going with!! so,zero machine work.swap and go!!!! im just putting the engine together now,i bought it used so im doing gaskets,bearings,timing chain etc.i can only do as much as i can afford ,a little bit at a time.
basically the gmpp crate engine SP350/357 is just a stock L31 vortec with the 7151 cam.you will make 360 horse and 410 foot pounds at the crank if you use this cam (P/N 12677151) and your L31 vortec
Anyone running this exact setup ? Yeah it is real easy out of the car. But should be easy either way. I can have engine and trans out in less than an hour but yeah I should have swapped it out. Looking forward to seeing how your build goes. Gonna be getting some parts together for my cam swap
headers and exhaust make a difference too. I went with Dyno Don's, large primaries down into a 3: exhaust. Most headers are too restrictive on a 350.
My L31 is stock too for now. I do have an air carb gap intake on top.
I bought an 83 Z28, red with t-tops from Arizona. No rust! I live in New England and most are rust buckets...
I need to swap my flexplate out to lineup and will be good to go. cracked into it tonight, placing an Amazon order to get the flywheel for this week, 2 day prime shipping baby!
Yeah I was gonna go with DD's as well but didn't wanna wait. Curious how long did it take you to recieve your headers? I went with the 2055s. And Jeggs 3 inch exhaust, Avs2 carb which runs great btw. And a dual plane gmpp intake.
someone suggested, after removing the bellhousing bolts, to swap in some 6" bolts to hold it in place, slide the tranny back, while I remove the flexplate
That would be me.
Just get the flex plate for a 86-92 Camaro/Firebird V8 and use the above technique to change it out.
see fast355(tgo member) he had this exact setup in a van and wow,it sounds wicked....he also had it fuel injected while mine(and possibly yours) are carbed applications.
