BBC to Gen V LT1/L86 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ripdog28 · 08-27-2020, 12:49 PM

Had the 462 with a Th400 for a while now and it just inst enjoyable unless your hammering on it. Even had it rebuilt two years ago with a Hyd roller cam and have not driven it, just started it a few times. Looking to make it so i can just cruise with and be more reliable or daily driver ish. I have a few options on the table but ill likely get a L86. I am debating on the 8L90E or a Tremec Magnum. I have 3.70 rear gears. The 8L will save me some money and keep the power brakes. Kind of torn. I believe the T56 will be more enjoyable but the 8L has a lot of benefits also with the super low 1st and the .50 8th. Hard to decide on what to do but the T56 will run about $3-4k more.

**mongocanfly** · 08-27-2020, 05:27 PM

T56=fun
8L=cruiser.
Be aware you'll have to work your way around the L86 having no ps pump...it. can be added though..
Not sure how the 3.70s will do with a .5od....if you have 28in tires you'll only be turning about 1440rpm at 65mph.. but it can make the low end worthless if you go to low on the rear ratio
http://www.csgnetwork.com/multirpmcalc.html

Researching....I'm seeing .65 for 8th gear,,,not .5.....which bumps the rpm up to 1876 at 65mph..that's if you have a 28in tire....
What size are your rear tires?
I've tried to shoot for 2000rpm at 65 on all mine...seems to be my sweet spot..

ripdog28 · 08-27-2020, 06:44 PM

already figured out the PS pump issue. If I go with the 8L, I am going to grab the Lokar E-shifter. Meant for the 6L but works for the 8L also and allow for manual shifting. Correct on the .65 ratio, had been looking at several transmissions last few days. got numbers all over my brain. Tires are 295/50 so 26.6" or 27" will be 1945rpm+ at 65. In SoCal, you will be run over doing 65 and typical traffic flows 75ish. That super low 1st gear with 3.70s will be tricky.

**bigmoe** · 08-27-2020, 08:40 PM

This one would be a struggle for me to decide. The 8L would be cool to have with the manual shift hooked up. You could also hook up the tow/haul mode for more aggressive up shift in drive. A manual trans would be nice too. If you like to hear the sound of your engine as it shifts it's a bit trickier with an automatic on the slower in town roads because by the time you get your revs up you're speeding. With a standard you can raise your shift rpms without tromping on the throttle as you slowly accelerate and listen to your sweet engine.

87chevy.com · 08-31-2020, 07:43 PM

Manual mode... not sure what your expecting... can bus will be staring at you like a fat kid in a candy store.
Tow haul button wont be like LS... can bus module..
Manual mode... need tap shift capable shifter.. or can bus module
When shifted past drive , there is a program associated with it... not sure what map it is which means not sure what to change in hp tuners...
And the detent after that also does something else.. this is on a gen 5 swap with 6l80e...
Ac is another one to deal with.. that one I got sorted out.. and you guessed it, can bus module lol..
Clint

**bigmoe** · 03-01-2021, 01:44 PM

Ripdog, what did you end up deciding?

LS short box · 03-01-2021, 05:32 PM

Just a note. Over on LS1tech in the automatic forum there is not a lot of love for that 8 speed auto trans. It's not known for being a great shifting trans. I had a 8 speed in my 2015 Silverado and it shifted hard 2-3 shift when cold. Had a hard down shift when I was slowing down for a stop light. Had it into the dealership for "reprograming" half a dozen times with very little improvement.

08-27-2020, 12:49 PM	#1
ripdog28 Registered User Join Date: Apr 2008 Location: Imperial Beach, CA Posts: 1,040	BBC to Gen V LT1/L86 Had the 462 with a Th400 for a while now and it just inst enjoyable unless your hammering on it. Even had it rebuilt two years ago with a Hyd roller cam and have not driven it, just started it a few times. Looking to make it so i can just cruise with and be more reliable or daily driver ish. I have a few options on the table but ill likely get a L86. I am debating on the 8L90E or a Tremec Magnum. I have 3.70 rear gears. The 8L will save me some money and keep the power brakes. Kind of torn. I believe the T56 will be more enjoyable but the 8L has a lot of benefits also with the super low 1st and the .50 8th. Hard to decide on what to do but the T56 will run about $3-4k more. __________________ 69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build.

08-27-2020, 05:27 PM	#2
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,583	Re: BBC to Gen V LT1/L86 T56=fun 8L=cruiser. Be aware you'll have to work your way around the L86 having no ps pump...it. can be added though.. Not sure how the 3.70s will do with a .5od....if you have 28in tires you'll only be turning about 1440rpm at 65mph.. but it can make the low end worthless if you go to low on the rear ratio http://www.csgnetwork.com/multirpmcalc.html Researching....I'm seeing .65 for 8th gear,,,not .5.....which bumps the rpm up to 1876 at 65mph..that's if you have a 28in tire.... What size are your rear tires? I've tried to shoot for 2000rpm at 65 on all mine...seems to be my sweet spot.. __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver Last edited by mongocanfly; 08-27-2020 at 05:40 PM.

08-27-2020, 06:44 PM	#3
ripdog28 Registered User Join Date: Apr 2008 Location: Imperial Beach, CA Posts: 1,040	Re: BBC to Gen V LT1/L86 already figured out the PS pump issue. If I go with the 8L, I am going to grab the Lokar E-shifter. Meant for the 6L but works for the 8L also and allow for manual shifting. Correct on the .65 ratio, had been looking at several transmissions last few days. got numbers all over my brain. Tires are 295/50 so 26.6" or 27" will be 1945rpm+ at 65. In SoCal, you will be run over doing 65 and typical traffic flows 75ish. That super low 1st gear with 3.70s will be tricky. __________________ 69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build.

08-27-2020, 08:40 PM	#4
bigmoe Senior Member Join Date: Oct 2014 Location: Brandon, Manitoba, Canada Posts: 952	Re: BBC to Gen V LT1/L86 This one would be a struggle for me to decide. The 8L would be cool to have with the manual shift hooked up. You could also hook up the tow/haul mode for more aggressive up shift in drive. A manual trans would be nice too. If you like to hear the sound of your engine as it shifts it's a bit trickier with an automatic on the slower in town roads because by the time you get your revs up you're speeding. With a standard you can raise your shift rpms without tromping on the throttle as you slowly accelerate and listen to your sweet engine.

08-31-2020, 07:43 PM	#5
87chevy.com BMW & ASE Master Certified Join Date: Feb 2004 Location: Houston, Texas Posts: 1,255	Re: BBC to Gen V LT1/L86 Manual mode... not sure what your expecting... can bus will be staring at you like a fat kid in a candy store. Tow haul button wont be like LS... can bus module.. Manual mode... need tap shift capable shifter.. or can bus module When shifted past drive , there is a program associated with it... not sure what map it is which means not sure what to change in hp tuners... And the detent after that also does something else.. this is on a gen 5 swap with 6l80e... Ac is another one to deal with.. that one I got sorted out.. and you guessed it, can bus module lol.. Clint __________________ 1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress

03-01-2021, 01:44 PM	#6
bigmoe Senior Member Join Date: Oct 2014 Location: Brandon, Manitoba, Canada Posts: 952	Re: BBC to Gen V LT1/L86 Ripdog, what did you end up deciding?

03-01-2021, 05:32 PM	#7
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 1,922	Re: BBC to Gen V LT1/L86 Just a note. Over on LS1tech in the automatic forum there is not a lot of love for that 8 speed auto trans. It's not known for being a great shifting trans. I had a 8 speed in my 2015 Silverado and it shifted hard 2-3 shift when cold. Had a hard down shift when I was slowing down for a stop light. Had it into the dealership for "reprograming" half a dozen times with very little improvement.



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