Stroking a LT-1 Motor during Rebuild-YES OR NO
09-30-2016, 07:59 AM
#21
Team Owner
Take the LT-1, if it's the original engine for the car, out of the car, place it in a couple of plastic trash bags, then store it in a safe, dry place. Go to the GM Performance website, and pick out a 383 crate motor, and install the crate motor in your car.
You'll retain the value of your original engine, and most likely spend less money of the complete engine. It will be 100% ready to drop in the car, have a known horsepower and torque rating, and will have a warranty.
Just my $0.02 worth
You'll retain the value of your original engine, and most likely spend less money of the complete engine. It will be 100% ready to drop in the car, have a known horsepower and torque rating, and will have a warranty.
Just my $0.02 worth
09-30-2016, 11:17 AM
#22
Take the LT-1, if it's the original engine for the car, out of the car, place it in a couple of plastic trash bags, then store it in a safe, dry place. Go to the GM Performance website, and pick out a 383 crate motor, and install the crate motor in your car.
You'll retain the value of your original engine, and most likely spend less money of the complete engine. It will be 100% ready to drop in the car, have a known horsepower and torque rating, and will have a warranty.
Just my $0.02 worth
You'll retain the value of your original engine, and most likely spend less money of the complete engine. It will be 100% ready to drop in the car, have a known horsepower and torque rating, and will have a warranty.
Just my $0.02 worth
We've done numerous 100% stock-appearing builds including many for some forum members up here, both SB's and BB's. Many are done for local resto shopand all MUST remain 100% stock looking. Right down to the OEM intake gaskets AND single-thick V/C gaskets. Most all of these are fully-rollered builds, lifters (mostly retro-hyd) and rockers. We can mill/square the decks without touching the original stamped pads, this is easy.
Thanks, Gary in N.Y.
P.S. The BB's are somewhat easier with keeping the "look" with the V/C area, SB's slightly more labor involved. All also have decent HP numbers, a recent BB (stroker) hit 525/530 with every OEM component, Q-jet to exh manifolds. Not really chasing numbers on this type build, basically bolt-together. Here's a shot of a recent SB, fully rollered. That original V/C has no gasket in place and clears all roller rockers nicely.
Last edited by GOSFAST; 09-30-2016 at 11:18 AM.
09-30-2016, 12:24 PM
#23
Intermediate
Wrap up that bad boy.....build a sneaky 406....and you will never think about a 383.
I love 383's.....but.....the 406 has the bore....a good 1/8 inch of it....
When you put real heads on a 406...they run like hell....
Put it to you this way friend....if you were going to stroke it....it would not make any sense to not add heads to support it....then a real cam and manifold....well at that point...the only point is the brag of the stamp number.....
A carefully built 350 LT-1 with modern tech and ported heads is a silky unit.....I had one. Well balanced engine....
But if you want to knock your socks off and look stock....build a 406.
Yes this post is biased
Jebby
I love 383's.....but.....the 406 has the bore....a good 1/8 inch of it....
When you put real heads on a 406...they run like hell....
Put it to you this way friend....if you were going to stroke it....it would not make any sense to not add heads to support it....then a real cam and manifold....well at that point...the only point is the brag of the stamp number.....
A carefully built 350 LT-1 with modern tech and ported heads is a silky unit.....I had one. Well balanced engine....
But if you want to knock your socks off and look stock....build a 406.
Yes this post is biased
Jebby
Last edited by saunderscx; 09-30-2016 at 12:29 PM.
09-30-2016, 12:38 PM
#24
Intermediate
Absolutely do NOT stroke an OEM 71 LT-1!!!!
You are 100% on the correct track...increase the compression to 10+:1, port the heads, intake, and a better cam (no one can see the change).
The bottom end of your engine is really good...forged crank, forged rods, forged pistons (lots of good forged pistons out there (I used JE Forged Racing pistons in my OEM L-82 9:1 with 64 CC AFR 180 aluminum heads with Felpro 1094 .015 head gasket))..total compression 10.2:1).
That is one of the iconic SBC engines used in the C3.....forget stroking a 350 into a 383...if you go that route use a different block into a 406 for real power gains over the 350...like jebbysan suggested^^ above. A properly equipped/built 355 with a forged bottom end like the L-82/LT-1 is more than a match for most 383's on the street. I would only stroke a run of the mill base motor 350/L-48 since it is a typical passenger car engine...
You are 100% on the correct track...increase the compression to 10+:1, port the heads, intake, and a better cam (no one can see the change).
The bottom end of your engine is really good...forged crank, forged rods, forged pistons (lots of good forged pistons out there (I used JE Forged Racing pistons in my OEM L-82 9:1 with 64 CC AFR 180 aluminum heads with Felpro 1094 .015 head gasket))..total compression 10.2:1).
That is one of the iconic SBC engines used in the C3.....forget stroking a 350 into a 383...if you go that route use a different block into a 406 for real power gains over the 350...like jebbysan suggested^^ above. A properly equipped/built 355 with a forged bottom end like the L-82/LT-1 is more than a match for most 383's on the street. I would only stroke a run of the mill base motor 350/L-48 since it is a typical passenger car engine...
09-30-2016, 12:43 PM
#25
Dr. Detroit
Member Since: Mar 2012
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If he goes with a 406 can does he need new springs ? How about other stuff like pulleys/belts/alt bracket/etc ? I've been thinking about mothballing my original numbers matching 350SB and upgrading. Until now I was thinking stroked 383 to keep cost of 'other stuff' to a minimum. This 350SB makes for a great cruiser but not much zing when you press the go pedal, especially rolling faster than 40 mph. Another concern for me is keeping the same low profile hood (see member icon to the left).... I don't think I can color match ~30 year old Pb paint (red now....originally white). My trans is a 400TH so assume that will bolt up to any GM block.
It will want headers for sure but you could run the stock LT-1 manifold as it was a very good piece.....just mill out the divider......
A 406 is most of the time built externally balanced so make sure you have the proper flexplate......and harmonic balancer for that matter.
I even have LT-1 covers on my own engine
In this photo the regulator is necessary for the 130gph pump I installed later......this photo is shortly after startup.....
And FYI the Holley HP series is one of the finest mixers out there........
Jebby
Last edited by Jebbysan; 09-30-2016 at 12:45 PM.
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saunderscx (09-30-2016)
09-30-2016, 01:27 PM
#26
Le Mans Master
If you rebuild a 350SB with a strong bottom end/forged pistons, keep Q-jet, and add performer manifold + heads + rocking assembly, about what type of HP is typical ? I've got an original numbers matching block. At this stage of the game I like the idea of the original look but I'm not opposed to change and I don't really care about NCRS stuff all that much. I do want more zip when I press the go pedal. If I could get something like 400 HP I'd be very happy. I think the base plate says 250 HP in stock config which is probably pretty much where I'm at now. Or maybe in my case an off the shelf crate engine makes more sense (just mothball the original) and save it.
If you go the crate engine route, then 383 all the way making 450+ gross HP...with slightly better torque throughout the rpm range..
09-30-2016, 01:32 PM
#27
Le Mans Master
If your going NCRS put a set of mini dome replacement pistons with the stock heads and that will give you compression a boost with the stock heads. Do some bowl work in your heads and some 1.6 rockers in it the bump in compression allows that cam to work better.
If not bag up the numbers matching motor and build another whatever you wish size. These guys are correct in a 383 making more torque, but built similarly horsepower is very close. If I was drag racing I'd build probably a 377 and gear the heck out of it.if I want torque to tow a boat I'd build a 454 plus engine.
I wouldn't take an LT-1 block and turn it into something else.a friend had a 70 LT-1 top flight car and when he was done showing it and winning every award there was he freshened the stock engine and we built a 396 small block to put in it.
If not bag up the numbers matching motor and build another whatever you wish size. These guys are correct in a 383 making more torque, but built similarly horsepower is very close. If I was drag racing I'd build probably a 377 and gear the heck out of it.if I want torque to tow a boat I'd build a 454 plus engine.
I wouldn't take an LT-1 block and turn it into something else.a friend had a 70 LT-1 top flight car and when he was done showing it and winning every award there was he freshened the stock engine and we built a 396 small block to put in it.
09-30-2016, 03:01 PM
#28
Intermediate
400+gross hp with good aluminum heads, 10+:1 compression and moderate roller cam. Better/Best aluminum heads like AFR's, more extreme roller cam, aftermarket intake, and 1 3/4 inch LTH headers...450+ Gross HP.
If you go the crate engine route, then 383 all the way making 450+ gross HP...with slightly better torque throughout the rpm range..
If you go the crate engine route, then 383 all the way making 450+ gross HP...with slightly better torque throughout the rpm range..
09-30-2016, 03:03 PM
#29
Intermediate
No......I used all of my stock 72' accessories......if you use a Dart Iron Eagle head the engine will be very close to weighing the same......
It will want headers for sure but you could run the stock LT-1 manifold as it was a very good piece.....just mill out the divider......
A 406 is most of the time built externally balanced so make sure you have the proper flexplate......and harmonic balancer for that matter.
I even have LT-1 covers on my own engine
In this photo the regulator is necessary for the 130gph pump I installed later......this photo is shortly after startup.....
And FYI the Holley HP series is one of the finest mixers out there........
Jebby
It will want headers for sure but you could run the stock LT-1 manifold as it was a very good piece.....just mill out the divider......
A 406 is most of the time built externally balanced so make sure you have the proper flexplate......and harmonic balancer for that matter.
I even have LT-1 covers on my own engine
In this photo the regulator is necessary for the 130gph pump I installed later......this photo is shortly after startup.....
And FYI the Holley HP series is one of the finest mixers out there........
Jebby
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Jebbysan (10-03-2016)
09-30-2016, 06:57 PM
#30
Burning Brakes
Thread Starter
This is a numbers matching engine. Therefore I have decided not to replace the intake manifold--already has an high performance dual plenium aluminum intake; can't replace the 780 cfm holley carb; can't replace the heads--numbers matching, etc. Only changes on the interior can be made. Some say replace the solid lifters with rollers--do they sound the same??
Left with:
increase compression from 9:1 to 10-10.5:1
porting the cc
porting the exhuast
bore out enough to clean the cylinders so it could be rebuilt again in the future
go with a more aggresive solid lifter cam--already have a NOS cam 3972182 whose specs are 242/254 .459/.485 116 LSA
dyno the engine to maximize carb/timing etc.
Has anyone used any of the new thermal coatings that supposedly decrease thermal transfer, decrease friction and help oil shedding
Engine builders I have talked said should be able to get 400HP from these mods.
I appreciate all your input. It has really helped me decide to keep it original and only made internal changes.
Left with:
increase compression from 9:1 to 10-10.5:1
porting the cc
porting the exhuast
bore out enough to clean the cylinders so it could be rebuilt again in the future
go with a more aggresive solid lifter cam--already have a NOS cam 3972182 whose specs are 242/254 .459/.485 116 LSA
dyno the engine to maximize carb/timing etc.
Has anyone used any of the new thermal coatings that supposedly decrease thermal transfer, decrease friction and help oil shedding
Engine builders I have talked said should be able to get 400HP from these mods.
I appreciate all your input. It has really helped me decide to keep it original and only made internal changes.
10-02-2016, 04:45 PM
#31
Team Owner
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St. Jude Donor '05
Edit: sounds like yet another was talked into staying stock
Last edited by cv67; 10-02-2016 at 09:02 PM.
10-03-2016, 12:05 PM
#32
Le Mans Master
Left with:
increase compression from 9:1 to 10-10.5:1
porting the cc
porting the exhuast
bore out enough to clean the cylinders so it could be rebuilt again in the future
go with a more aggresive solid lifter cam--already have a NOS cam 3972182 whose specs are 242/254 .459/.485 116 LSA
dyno the engine to maximize carb/timing etc.
increase compression from 9:1 to 10-10.5:1
porting the cc
porting the exhuast
bore out enough to clean the cylinders so it could be rebuilt again in the future
go with a more aggresive solid lifter cam--already have a NOS cam 3972182 whose specs are 242/254 .459/.485 116 LSA
dyno the engine to maximize carb/timing etc.
So far I haven't read one logical response as to why not. It's just a bunch of people talking out their ***.
10-03-2016, 01:34 PM
#33
Team Owner
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St. Jude Donor '05
why buy a car in the first place and keep it so you cant enjoy it cause of what some unknown may think
I really worry about what the next guy will think of when he winds up with my woman maybe one day.
I really worry about what the next guy will think of when he winds up with my woman maybe one day.
10-03-2016, 01:43 PM
#34
Drifting
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2022 C3 of the Year Finalist - Unmodified
You may not need to bore - Mine, with ~ 100K miles on it, maybe, I don't really know, bores are 4.002/4.003. None have more than .001 taper or more than .002 out of round. Back in the dark ages one could get pistons +.001. I don't know if they are still available.
This time around it just needs a hone and new rings (well along with all the other usual stuff).
