LT1 Heads/LT1 rebuild
Thread Starter
Instructor
Joined: Jul 2000
Posts: 226
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From: washington MI
LT1 Heads/LT1 rebuild
I just purchased a nice LT1 engine, with manual trans, only problem it needs more power, before being slid into my 1968 Corvette. http://216.254.32.120/jan99/p68.html I was thinking of doing a 383 combined with a paxton type supercharger.
Right now, I have the heads off and am preparing to have the head guy start grinding. I was wondering if anyone has sandwiched 2.05/2.08 intake vavles or 1.66 exhaust valves. Looking at the metal around the stock heads there doesn't seem much to play with. So what are the largest valve sizes anyone has put in?
Also what areas are you seeing the most from during a cleanup of the heads? Looking at the area machined for the pushrods, its seems that that area will reduce the ammount of material I can take off the insides of the runner.
Any specs that you can share would be appreciated.
Mike
Right now, I have the heads off and am preparing to have the head guy start grinding. I was wondering if anyone has sandwiched 2.05/2.08 intake vavles or 1.66 exhaust valves. Looking at the metal around the stock heads there doesn't seem much to play with. So what are the largest valve sizes anyone has put in?
Also what areas are you seeing the most from during a cleanup of the heads? Looking at the area machined for the pushrods, its seems that that area will reduce the ammount of material I can take off the insides of the runner.
Any specs that you can share would be appreciated.
Mike
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: LT1 Heads/LT1 rebuild (Mr Y Car)
The stock seats on LT1 heads will go as far as 2.0/1.56 or maybe 1.57". I dont think you can fit much more than a 2.02/1.60 in the head and maintain functionality. I am running 2.0/1.56 valves in mine and it seems to make good power.
Thread Starter
Instructor
Joined: Jul 2000
Posts: 226
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From: washington MI
Re: LT1 Heads/LT1 rebuild
Thanks for the input. Am shooting for 2.02 intake now and 1.6 exhaust, hoping for flow of about 260cfm @.50 on intake and 200cfm @50 on exhaust. Goning to need to flow some good exhaust numbersto accomodate the supercharger planned for it.
Now am trying to find a good discount parts supplier to buy the goodies need to go with this setup. I notice Summit and Jegs have a pucity of LT1 components in their catalogs. Where do most of the folk on here go when they want high quality LT1 components.
Am looking at adding a Forged 3.75 crank; some 5.7 oliver, manley,lunati or summit H beam rods; JE 20cc dish pistons, child and alberts rings, and milodan 4 bolt splayed main caps on the lower end.
After Porting the heads will be looking at a 1.6 roller rockers, new valve springs, 2.02 in, 1.6 exhaust valves, and a @.50 480/480lift and about 230/230 duration. Hopefully this will go well with the supercharger.
On the injector side runng svo 30lbs. 58 mmTB.
I hope this combo should work well, haven't run all the numbers yet, and am open for suggestions on where to buy and how to change the combination for best performance. This will be attached to a 6 speed and a 3.73 rearend. Going for a strong 1/4 mile car and an occasional driver.
thanks for the advice
Mike
Now am trying to find a good discount parts supplier to buy the goodies need to go with this setup. I notice Summit and Jegs have a pucity of LT1 components in their catalogs. Where do most of the folk on here go when they want high quality LT1 components.
Am looking at adding a Forged 3.75 crank; some 5.7 oliver, manley,lunati or summit H beam rods; JE 20cc dish pistons, child and alberts rings, and milodan 4 bolt splayed main caps on the lower end.
After Porting the heads will be looking at a 1.6 roller rockers, new valve springs, 2.02 in, 1.6 exhaust valves, and a @.50 480/480lift and about 230/230 duration. Hopefully this will go well with the supercharger.
On the injector side runng svo 30lbs. 58 mmTB.
I hope this combo should work well, haven't run all the numbers yet, and am open for suggestions on where to buy and how to change the combination for best performance. This will be attached to a 6 speed and a 3.73 rearend. Going for a strong 1/4 mile car and an occasional driver.
thanks for the advice
Mike
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: LT1 Heads/LT1 rebuild (Mr Y Car)
Try giving Chris Konikowski a call at Speed Demon motorsports (Forum Supporting Vendor) or email him at ChrisK@speeddemonmotorsports.com
He can help you out on the head work too if you need. Good prices and service.
FWIW, if you are going to supercharge it, you will most likely need larger injectors than 30lb'ers. Maybe 36 or even larger depending on the timeframe and if you want to change injectors again when the blower goes on. You could probably find a better cam than what you listed too. A good blower cam usually has a longer duration on the exhaust as well. The Comp Cam 305 may be a better choice for all around. If you are looking strictly for drag racing and the occasional cruise, a 230/230, .480/.480 is pretty mild on the lift side for a hydraulic roller especially with 1.6 rockers and a 383 stroker.
He can help you out on the head work too if you need. Good prices and service.
FWIW, if you are going to supercharge it, you will most likely need larger injectors than 30lb'ers. Maybe 36 or even larger depending on the timeframe and if you want to change injectors again when the blower goes on. You could probably find a better cam than what you listed too. A good blower cam usually has a longer duration on the exhaust as well. The Comp Cam 305 may be a better choice for all around. If you are looking strictly for drag racing and the occasional cruise, a 230/230, .480/.480 is pretty mild on the lift side for a hydraulic roller especially with 1.6 rockers and a 383 stroker.
Thread Starter
Instructor
Joined: Jul 2000
Posts: 226
Likes: 0
From: washington MI
Re: LT1 Heads/LT1 rebuild
My Head guy has been busy and just dropped off my freshly ported and polished LT1 heads. There not completely done yet, just ready to be set up to put new larger seats in. then a final finshing touch to the heads.
Take a gander at this work and comment if you see any areas of improvement to his porting.
Bowl work (involved recontouring bowl and removing part of the ledge above the plug.)
intake work(gasket matched, removed some from lower part of runner and streamlined around valve seat)
exhaust work(gasket matched, except for lower portion of the D exhaust, some metal removed inside exhaust)
This is my mechanics first lt1 set of heads, he usually does F*rds and monster trucks, as well as ATV's and snowmobiles. So any comments would be appreciated.
Mike
[Modified by Mr Y Car, 10:28 PM 12/18/2001]
Take a gander at this work and comment if you see any areas of improvement to his porting.
Bowl work (involved recontouring bowl and removing part of the ledge above the plug.)
intake work(gasket matched, removed some from lower part of runner and streamlined around valve seat)
exhaust work(gasket matched, except for lower portion of the D exhaust, some metal removed inside exhaust)
This is my mechanics first lt1 set of heads, he usually does F*rds and monster trucks, as well as ATV's and snowmobiles. So any comments would be appreciated.
Mike
[Modified by Mr Y Car, 10:28 PM 12/18/2001]
Heel & Toe
Joined: Sep 2001
Posts: 24
Likes: 0
From: Allen TX
Re: LT1 Heads/LT1 rebuild (Mr Y Car)
You may want to take a gander at the "Forced Induction"forum at http://www.camaroz28.com/messagebd/index.html
Te supercharged 383 LT1 is a fairly common buildup for the F-body and there is a ton of info on various parts combinations at the above mentioned site.
See ya,
John
[Modified by J Winkeler, 4:44 PM 12/19/2001]
Te supercharged 383 LT1 is a fairly common buildup for the F-body and there is a ton of info on various parts combinations at the above mentioned site.
See ya,
John
[Modified by J Winkeler, 4:44 PM 12/19/2001]
Instructor
Joined: Sep 2001
Posts: 168
Likes: 0
From: Ottawa Ont
Re: LT1 Heads/LT1 rebuild (Mr Y Car)
Just wondering if the small ledge that was removed would cause and compression loss. I was looking at my LT-4 head and thought that if you remove the rectangular ledge behind the spark plug hole you run the chance of increasing the cc size of your combustion chamber?????
Maybe i'm nuts ???? :crazy:
Maybe i'm nuts ???? :crazy:
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