1971 LT1 Engine Rebuild ?
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Put the original engine on the stand, pickled, and build a sleeper 383 that looks 100% correct...but makes far more power.
You obviously like to drive your LT-1 hard, which is a Good Thing. But as you've got a high-value car based on that engine...mitigating the risk seems like Smart Money to me...
You obviously like to drive your LT-1 hard, which is a Good Thing. But as you've got a high-value car based on that engine...mitigating the risk seems like Smart Money to me...
Drifting
Joined: Jan 2012
Posts: 1,908
Likes: 129
From: Fredericksburg Virginia
Only thing is if he's actually trying to get the car flighted, having a pickled engine isn't going to get the points. He has to use his block/heads and have the engine APPEAR correct. He can, of course, modify the internals...
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
It ain't gonna get "flighted" with flowtech headers and magnaflow mufflers...and there's about 1,000 ways a shop can screw this up, not the least of which is taking a deep deck cut and removing the stamping...
Race Director
Joined: Feb 2001
Posts: 11,053
Likes: 1,956
From: Grapevine Tx
2018 C3 of Year Finalist
2016 C3 of the Year Finalist
Put the original engine on the stand, pickled, and build a sleeper 383 that looks 100% correct...but makes far more power.
You obviously like to drive your LT-1 hard, which is a Good Thing. But as you've got a high-value car based on that engine...mitigating the risk seems like Smart Money to me...
You obviously like to drive your LT-1 hard, which is a Good Thing. But as you've got a high-value car based on that engine...mitigating the risk seems like Smart Money to me...
If I ever pull my engine, I'll modernize the internals and keep the external appearance stock.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
On a roll-away an engine takes up maybe a 3'x4' square. Hard to imagine owning a classic 'Vette without at least that much space.
But even if that were the case...I'd spend the $ for a storage space vs. running an engine that was 2/3ds the value of the car hard. Break it...and it's just another LT-1 clone value-wise.
It's his car; he gets to make up his own mind - this is just one guy's take.
But even if that were the case...I'd spend the $ for a storage space vs. running an engine that was 2/3ds the value of the car hard. Break it...and it's just another LT-1 clone value-wise.
It's his car; he gets to make up his own mind - this is just one guy's take.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 121
From: Millington Illinois
St. Jude Donor '08-'09
I would bump the compression up about a point, 3.75 forged internally balanced crank, Pocket port and clean up the ports on the stock heads with a 3 angle valve job, port match the intake and heads after a clean up cut on the head deck, Full roller rockers 1.52 would be my choice (make sure they clear stock valve covers), and go with this cam. Nitrided : http://www.compcams.com/Company/CC/c...?csid=232&sb=2
These lifters: http://www.compperformancegroupstore...de=PontLifters
correct pressure Beehive springs to avoid machining heads and better flowing mufflers, take the small hit as the mufflers are likely not stock anyway. I would also clean up the ports and any obvious restriction or flash on the exhaust manifolds internally. Make sure your exhaust flapper is working well. 1094 head gasket. No block decking at all! You might get by with a .010 overbore and there are .010 pistons available. Factory cam is 116 LSA with little bottom end and wide lash. The cam linked has the sound, better lift, better LSA, better operating range and tighter lash for less wear. You should be able to get 400 HP, better bottom end and torque, right sound and the judges can crawl all over it and not find anything to pick apart.
These lifters: http://www.compperformancegroupstore...de=PontLifters
correct pressure Beehive springs to avoid machining heads and better flowing mufflers, take the small hit as the mufflers are likely not stock anyway. I would also clean up the ports and any obvious restriction or flash on the exhaust manifolds internally. Make sure your exhaust flapper is working well. 1094 head gasket. No block decking at all! You might get by with a .010 overbore and there are .010 pistons available. Factory cam is 116 LSA with little bottom end and wide lash. The cam linked has the sound, better lift, better LSA, better operating range and tighter lash for less wear. You should be able to get 400 HP, better bottom end and torque, right sound and the judges can crawl all over it and not find anything to pick apart.
Melting Slicks
Joined: Feb 2004
Posts: 2,111
Likes: 32
From: Damascus MD
Lt-1
If I owned a 60k mile original LT-1 and it was blowing a little blue smoke I would first pull the heads. Actually before you pull the heads get good solid compression numbers for each cylinder. Bad valve guides and seals will not affect the compression. If numbers are good chances are the bottom end is fine.
60k miles is really not bad at all for the bottom end of a chevy 350 plus you will be able to inspect for anything unusual once the heads and oil pan are removed before doing anything drastic. I have a 100k mile L46 which is an identical bottom end in every way and no problems with great compression, no smoke and no tapping. I just changed gaskets and put in a new Cloyes timing gear set.
Install a new original grind cam and lifters. Then have the intake and heads port matched and have someone that really knows what they are doing pocket port and clean up the heads. Just clean them up. Nothing too exotic. I definitely concur with raising the compression a point or so as the 70 LT-1 was rated at 11:1. The heads made the difference. The trick back in the day for the 71 and later LT-1s was to find a set of earlier 186 heads and have them pocket ported. Both the 70 and 71 heads have the big valves but the little extra compression from the 186 heads really wakes up the LT-1 as that is how it was originally designed to be run. However, I would stick with the stock 71 heads since today's pump gas is not conducive to higher compression with cast iron heads. My 70 11:1 L46 really loves the CAM 2 racing fuel but that gets REALLY expensive.
After the top end rebuild, recurve the distributor, install a nice set of headers and be done with it while not spending a fortune. Maybe top it off with a dyno tune to get the optimum Air/Fuel mixture from the holly carb.
Now if you plan to go racing that is another story. Bag the original motor and save it for another day. Then install a nice 383 stroker.
Love 63 Mako's suggestion too with the all stock look and added performance.
Bill
60k miles is really not bad at all for the bottom end of a chevy 350 plus you will be able to inspect for anything unusual once the heads and oil pan are removed before doing anything drastic. I have a 100k mile L46 which is an identical bottom end in every way and no problems with great compression, no smoke and no tapping. I just changed gaskets and put in a new Cloyes timing gear set.
Install a new original grind cam and lifters. Then have the intake and heads port matched and have someone that really knows what they are doing pocket port and clean up the heads. Just clean them up. Nothing too exotic. I definitely concur with raising the compression a point or so as the 70 LT-1 was rated at 11:1. The heads made the difference. The trick back in the day for the 71 and later LT-1s was to find a set of earlier 186 heads and have them pocket ported. Both the 70 and 71 heads have the big valves but the little extra compression from the 186 heads really wakes up the LT-1 as that is how it was originally designed to be run. However, I would stick with the stock 71 heads since today's pump gas is not conducive to higher compression with cast iron heads. My 70 11:1 L46 really loves the CAM 2 racing fuel but that gets REALLY expensive.
After the top end rebuild, recurve the distributor, install a nice set of headers and be done with it while not spending a fortune. Maybe top it off with a dyno tune to get the optimum Air/Fuel mixture from the holly carb.
Now if you plan to go racing that is another story. Bag the original motor and save it for another day. Then install a nice 383 stroker.
Love 63 Mako's suggestion too with the all stock look and added performance.
Bill
Last edited by 1974ta; Feb 20, 2014 at 08:32 PM. Reason: Spelling and add
Le Mans Master
Joined: Oct 2010
Posts: 6,903
Likes: 834
From: melbourne florida
2023 C3 of the Year Finalist - Modified
the 64 cc chambers will only get you to about 9.9 or 10-1 compression.
but actually that is about perfect. you should be fine with iron heads at that compression. i agree with that cam that would be a nice package.
but actually that is about perfect. you should be fine with iron heads at that compression. i agree with that cam that would be a nice package.
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Melting Slicks
Joined: Feb 2004
Posts: 2,111
Likes: 32
From: Damascus MD
Pistons
Oops! Forgot they changed the pistons too. 10:1 might be just about perfect
Bill
Race Director
Joined: Feb 2001
Posts: 11,053
Likes: 1,956
From: Grapevine Tx
2018 C3 of Year Finalist
2016 C3 of the Year Finalist
I would bump the compression up about a point, 3.75 forged internally balanced crank, Pocket port and clean up the ports on the stock heads with a 3 angle valve job, port match the intake and heads after a clean up cut on the head deck, Full roller rockers 1.52 would be my choice (make sure they clear stock valve covers), and go with this cam. Nitrided : http://www.compcams.com/Company/CC/c...?csid=232&sb=2
These lifters: http://www.compperformancegroupstore...de=PontLifters
correct pressure Beehive springs to avoid machining heads and better flowing mufflers, take the small hit as the mufflers are likely not stock anyway. I would also clean up the ports and any obvious restriction or flash on the exhaust manifolds internally. Make sure your exhaust flapper is working well. 1094 head gasket. No block decking at all! You might get by with a .010 overbore and there are .010 pistons available. Factory cam is 116 LSA with little bottom end and wide lash. The cam linked has the sound, better lift, better LSA, better operating range and tighter lash for less wear. You should be able to get 400 HP, better bottom end and torque, right sound and the judges can crawl all over it and not find anything to pick apart.
These lifters: http://www.compperformancegroupstore...de=PontLifters
correct pressure Beehive springs to avoid machining heads and better flowing mufflers, take the small hit as the mufflers are likely not stock anyway. I would also clean up the ports and any obvious restriction or flash on the exhaust manifolds internally. Make sure your exhaust flapper is working well. 1094 head gasket. No block decking at all! You might get by with a .010 overbore and there are .010 pistons available. Factory cam is 116 LSA with little bottom end and wide lash. The cam linked has the sound, better lift, better LSA, better operating range and tighter lash for less wear. You should be able to get 400 HP, better bottom end and torque, right sound and the judges can crawl all over it and not find anything to pick apart.
Burning Brakes
Joined: Aug 2007
Posts: 1,084
Likes: 8
From: Illinois
I agree with 63 Mako--I need to email you after they open the engine up and tell me what they find. I had the valve seals replaced--mechanic said the engine had not been opened before and a compression test was done:
#1-185
#2-190
#3-180
#4-190
#5-175
#6-175
#7-185
#8-190
I have had most of the original parts rebuild and reinstalled by me including AIR system;TI system including distributor, the 4 speed; he steering gear, the radiator blown out-cleaned and recored, new springs, bearings, trailing arms rebuilt, brakes all redone, new wiring harness, holley carb, the list goes on and on. I also completely redid the interior myself. As I said the muffles are not originial but everything else is down to the fuses, wiper blades, and exhaust manifolds and all numbers match.
I can read the manuals and use this forum to most things but I will not attempt the engine part.
I loved the sound of the redone engine that was posted.
I will be taking the car over to Plainfield Indiana in April when the weather cleans and the snow is gone--I hope. Anyone used Mike Norris Motorsports/Raymonds Performance.
#1-185
#2-190
#3-180
#4-190
#5-175
#6-175
#7-185
#8-190
I have had most of the original parts rebuild and reinstalled by me including AIR system;TI system including distributor, the 4 speed; he steering gear, the radiator blown out-cleaned and recored, new springs, bearings, trailing arms rebuilt, brakes all redone, new wiring harness, holley carb, the list goes on and on. I also completely redid the interior myself. As I said the muffles are not originial but everything else is down to the fuses, wiper blades, and exhaust manifolds and all numbers match.
I can read the manuals and use this forum to most things but I will not attempt the engine part.
I loved the sound of the redone engine that was posted.
I will be taking the car over to Plainfield Indiana in April when the weather cleans and the snow is gone--I hope. Anyone used Mike Norris Motorsports/Raymonds Performance.
Thread Starter
Instructor
Joined: Aug 2011
Posts: 123
Likes: 7
Thought I would give a up-date
I did have the engine pulled last March
Everything inside was replaced and re-done, and kept all as per stock
Engine(thankfully) did not have to be re-decked, so #'s are still as per original
Engine rebuilder confirmed that this engine was never previously opened
I did see all the old parts and you can see the wear
Since having the engine back in, last summer cruising was awesome
Not a drop of oil gets burned
Oil pressure on the gauge stays much higher then previous(stays app at middle no matter how hot)
Never do I see smoke
Engine feels much stronger
Really glad I had this done
Cant wait for the snow to disappear so cruising seaon can start
Next winter I will have the car in for painting, then I am done
I did have the engine pulled last March
Everything inside was replaced and re-done, and kept all as per stock
Engine(thankfully) did not have to be re-decked, so #'s are still as per original
Engine rebuilder confirmed that this engine was never previously opened
I did see all the old parts and you can see the wear
Since having the engine back in, last summer cruising was awesome
Not a drop of oil gets burned
Oil pressure on the gauge stays much higher then previous(stays app at middle no matter how hot)
Never do I see smoke
Engine feels much stronger
Really glad I had this done
Cant wait for the snow to disappear so cruising seaon can start
Next winter I will have the car in for painting, then I am done
I agree with 63 Mako--I need to email you after they open the engine up and tell me what they find. I had the valve seals replaced--mechanic said the engine had not been opened before and a compression test was done:
#1-185
#2-190
#3-180
#4-190
#5-175
#6-175
#7-185
#8-190
I have had most of the original parts rebuild and reinstalled by me including AIR system;TI system including distributor, the 4 speed; he steering gear, the radiator blown out-cleaned and recored, new springs, bearings, trailing arms rebuilt, brakes all redone, new wiring harness, holley carb, the list goes on and on. I also completely redid the interior myself. As I said the muffles are not originial but everything else is down to the fuses, wiper blades, and exhaust manifolds and all numbers match.
I can read the manuals and use this forum to most things but I will not attempt the engine part.
I loved the sound of the redone engine that was posted.
I will be taking the car over to Plainfield Indiana in April when the weather cleans and the snow is gone--I hope. Anyone used Mike Norris Motorsports/Raymonds Performance.
#1-185
#2-190
#3-180
#4-190
#5-175
#6-175
#7-185
#8-190
I have had most of the original parts rebuild and reinstalled by me including AIR system;TI system including distributor, the 4 speed; he steering gear, the radiator blown out-cleaned and recored, new springs, bearings, trailing arms rebuilt, brakes all redone, new wiring harness, holley carb, the list goes on and on. I also completely redid the interior myself. As I said the muffles are not originial but everything else is down to the fuses, wiper blades, and exhaust manifolds and all numbers match.
I can read the manuals and use this forum to most things but I will not attempt the engine part.
I loved the sound of the redone engine that was posted.
I will be taking the car over to Plainfield Indiana in April when the weather cleans and the snow is gone--I hope. Anyone used Mike Norris Motorsports/Raymonds Performance.