L99 Max. Bore - ???
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Teching In
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L99 Max. Bore - ??? I tried to search for an answer to this, forgive me if I missed it. Does anyone know if / or has anyone bored a L99 (4.3l caprice V8) to 4 inches? Besides the bore, are the blocks similar; as in would I want to bore a L99 block if I could? I though I read something about LT1 heads not working with an L99. Yes, I want a 302 LT1.
millis
millis
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From: Decatur, TN (N-W of Athens)
4.3 is the same block as the V8 minus 2. So you can put 400 pistons in them. Or at least, the older ones (like a 90 block). So yea, you could put 6" rods and have the 4.125" 400 pistons and have a 4.9L 301ci 6cyl baby LT1 
(I pluged all it into Desktop Dyno and it is 300.7ci and 821.2cc/cyl or 4925cc total) Get me cam specs, with BTDC, BBDC, ATDC, ABDC and lift. I can plug all that in then and give an approx power rating.
EDIT: I just tossed in some auto calc numbers @ .500/.500 and it's showing around normal LS1 numbers heh 313hp @ 5500 and 352tq @ 3500. Over 330tq 3000-4500. @ 4500 it's 341tq.
Now, those numbers are "grain of salt" type. It uses the same numbers for the cam specs
(I pluged all it into Desktop Dyno and it is 300.7ci and 821.2cc/cyl or 4925cc total) Get me cam specs, with BTDC, BBDC, ATDC, ABDC and lift. I can plug all that in then and give an approx power rating.EDIT: I just tossed in some auto calc numbers @ .500/.500 and it's showing around normal LS1 numbers heh 313hp @ 5500 and 352tq @ 3500. Over 330tq 3000-4500. @ 4500 it's 341tq.
Now, those numbers are "grain of salt" type. It uses the same numbers for the cam specs
Last edited by Formula350; Apr 14, 2007 at 02:52 AM.
I have one that I bored .060. I doubt that you can go much more than that. To get to a 4.00 bore you have to bore more than .200!! I think that you will have to bite the bullet and find an lt1 block.
Good Luck,
Daren
Good Luck,
Daren
Originally Posted by Formula350
4.3 is the same block as the V8 minus 2. So you can put 400 pistons in them. Or at least, the older ones (like a 90 block). So yea, you could put 6" rods and have the 4.125" 400 pistons and have a 4.9L 301ci 6cyl baby LT1 (I pluged all it into Desktop Dyno and it is 300.7ci and 821.2cc/cyl or 4925cc total) Get me cam specs, with BTDC, BBDC, ATDC, ABDC and lift. I can plug all that in then and give an approx power rating.
(I pluged all it into Desktop Dyno and it is 300.7ci and 821.2cc/cyl or 4925cc total) Get me cam specs, with BTDC, BBDC, ATDC, ABDC and lift. I can plug all that in then and give an approx power rating. TECH Senior Member
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From: Decatur, TN (N-W of Athens)
Yea, sorry I misread >_< I plugged in the 265 before I closed the program, and it was all weird. That's why I didn't post anything. It was making max power @ 7-8K RPM and torque around 5000-5500. It didn't start making ANY power till 2000RPM. So I think something is up with the program, or maybe that is just a weird motor *shrug*.
I figure the 4.3 would be the same LT1 block as the 350, and be able to be bored out. I mentioned this in another thread about the L99. I'd like to see a LT1 with the L99 crank for a de-stroker that would be a crazy reving motor due to the shorter throw. Maybe toss in the 6" rods for a bit more, it would probably make a 327 by then. The L99 is a 3" crank, the 327 is 3.280. Then you could still bore the original LT1 over more and get back to 350 and have a nice high reving power house. It'd make a really sweet track motor (not drag, but race). Man, now I want to plug these numbers in
EDIT: heh Yep. 349cid after being 4.125 bore x 3.270 stroke and it makes the SAME power as a normal LT1. So imagine throwing bolt-ons and having it rev more.
BTW I remember Wikipedia having info on the babyLT1.
I figure the 4.3 would be the same LT1 block as the 350, and be able to be bored out. I mentioned this in another thread about the L99. I'd like to see a LT1 with the L99 crank for a de-stroker that would be a crazy reving motor due to the shorter throw. Maybe toss in the 6" rods for a bit more, it would probably make a 327 by then. The L99 is a 3" crank, the 327 is 3.280. Then you could still bore the original LT1 over more and get back to 350 and have a nice high reving power house. It'd make a really sweet track motor (not drag, but race). Man, now I want to plug these numbers in
EDIT: heh Yep. 349cid after being 4.125 bore x 3.270 stroke and it makes the SAME power as a normal LT1. So imagine throwing bolt-ons and having it rev more.
BTW I remember Wikipedia having info on the babyLT1.
Last edited by Formula350; Apr 14, 2007 at 03:35 PM.
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Originally Posted by millis
Anyone???
Formula350, thanks for the suggestion, that would be an interesting motor indeed, but I am only interested in a V8.
millis
Formula350, thanks for the suggestion, that would be an interesting motor indeed, but I am only interested in a V8.
millis
I said it before. I don't believe that you can bore an L99 that far (you will not be able to take an LT1 block to 4.125" either). Your best bet would be to find an LT1 block and put the L99 crank in it. That way you can use any of the available LT1/LT4 heads. The LT4's light weight valves would be a big plus in this application, because you will have to turn it pretty high.
I had an L99 in my Camaro for a while that ran 7.8's in the 1/8th with all stock internals and a Lunati cam and springs. That was at 3300 lbs. It made around 315 rwhp and was a blast to drive.
I have another L99 in my shop that has custom .060 pistons and a bunch of trick parts. It will make a bunch more HP than the old motor. I will be running stock intake castings with the small (1.84" valves).
A 302 built with just a few good parts would be a bunch of fun. Don't count it out on the drag strip either!
Good Luck,
Daren
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Teching In
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Wow, totally skipped over your post...sorry about that. That is good information to know. There is a L99, 0 bids on ebay for $650 w/ free shipping (I think) and the guy has a LT1 he will sell for $500, could get both for $1000. How hard would it be to re program a stock pcm.
Although, I think I am going Gen I. I already have a forged crank out of a small journal 283. Now I need a small journal 327 block.
Although, I think I am going Gen I. I already have a forged crank out of a small journal 283. Now I need a small journal 327 block.
Originally Posted by millis
Wow, totally skipped over your post...sorry about that. That is good information to know. There is a L99, 0 bids on ebay for $650 w/ free shipping (I think) and the guy has a LT1 he will sell for $500, could get both for $1000. How hard would it be to re program a stock pcm.
Although, I think I am going Gen I. I already have a forged crank out of a small journal 283. Now I need a small journal 327 block.
Although, I think I am going Gen I. I already have a forged crank out of a small journal 283. Now I need a small journal 327 block.
Good Luck,
Daren
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From: Decatur, TN (N-W of Athens)
Found this site, it's mostly Corvette related, but mentions some interesting stuff with the 265 and iron heads. The 265 rods are just a hair LONGER than the 350's, and the 95+ Iron heads flow 20% more than the other year Alu (dyno tested, it says).
http://www.automotiverebuilder.com/ar/ar99928.htm
http://www.automotiverebuilder.com/ar/ar99928.htm
Thread Starter
Teching In
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Daren,
I may be interested. I did not know that there is a carb intake for the LT1, although I was thinking about looking into that. I am going to get in contact with the guy about the LT1 and if I get it I would trade you straight up. Then all I would need to do is buy the rods new (I assume they still sell the 5.94" rods). I really like the idea of a carb'd, reverse flow, Gen II, 302. Do you have any more information about how to setup an LT1 for a carb? BTW, the LT1 I am looking at is an iron headed caprice LT1, so eventually I would get new heads.
Sigh, I looked up the number on my 283 crank and it is cast...not forged like I thought.
millis
I may be interested. I did not know that there is a carb intake for the LT1, although I was thinking about looking into that. I am going to get in contact with the guy about the LT1 and if I get it I would trade you straight up. Then all I would need to do is buy the rods new (I assume they still sell the 5.94" rods). I really like the idea of a carb'd, reverse flow, Gen II, 302. Do you have any more information about how to setup an LT1 for a carb? BTW, the LT1 I am looking at is an iron headed caprice LT1, so eventually I would get new heads.
Sigh, I looked up the number on my 283 crank and it is cast...not forged like I thought.
millis
I had this idea years ago but everyone shot it down and called me stupid. I think it would be a very interesting build. Id get an LT1 block and order a forged 3.00 stroke crank and some forged pistons. Make it rev like crazy to 7000rpm the run out of fuel maps 
Jeremy
Jeremy
Originally Posted by LT1Z/28
how would you get a 302ci out of a L99, this sounds very interesting, the gen 1 302's are nuts, lol.
Originally Posted by millis
Daren,
I may be interested. I did not know that there is a carb intake for the LT1, although I was thinking about looking into that. I am going to get in contact with the guy about the LT1 and if I get it I would trade you straight up. Then all I would need to do is buy the rods new (I assume they still sell the 5.94" rods). I really like the idea of a carb'd, reverse flow, Gen II, 302. Do you have any more information about how to setup an LT1 for a carb? BTW, the LT1 I am looking at is an iron headed caprice LT1, so eventually I would get new heads.
Sigh, I looked up the number on my 283 crank and it is cast...not forged like I thought.
millis
I may be interested. I did not know that there is a carb intake for the LT1, although I was thinking about looking into that. I am going to get in contact with the guy about the LT1 and if I get it I would trade you straight up. Then all I would need to do is buy the rods new (I assume they still sell the 5.94" rods). I really like the idea of a carb'd, reverse flow, Gen II, 302. Do you have any more information about how to setup an LT1 for a carb? BTW, the LT1 I am looking at is an iron headed caprice LT1, so eventually I would get new heads.
Sigh, I looked up the number on my 283 crank and it is cast...not forged like I thought.
millis
$500.00 is not bad for an LT1, but I would rather have the aluminum heads. If you are on a budget and will just be doing a clean-up, go with 561's (1997). You will be surprised at the deals you will find on LT1 stuff if you are patient. I have purchased several good blocks for $100.00-$150.00. Stock aluminum heads can be had for as little as $200.00.
What would this motor be going in? The carb intake bolts on and uses a conventional GM distributor. GM sells a plate to block off the opti hole.
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Teching In
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Daren,
The plan is the L99 crank and rods and LT1 pistons, I found this recipe a long time ago and did the math to make sure it lined up correctly, it checks out. I think your formula sounds correct, forged pistons, factory Al heads, I will just have to keep a watch for an 561. What is a good way of coming across a 561 engine (internet, junkyard, other)? I am also interested in your L99 rods, if you are selling them. Send me an email - doobscooter@yahoo.com - on price of the L99 crank and rods.
Oh, the motor would be going in a 71 Camaro.
millis
The plan is the L99 crank and rods and LT1 pistons, I found this recipe a long time ago and did the math to make sure it lined up correctly, it checks out. I think your formula sounds correct, forged pistons, factory Al heads, I will just have to keep a watch for an 561. What is a good way of coming across a 561 engine (internet, junkyard, other)? I am also interested in your L99 rods, if you are selling them. Send me an email - doobscooter@yahoo.com - on price of the L99 crank and rods.
Oh, the motor would be going in a 71 Camaro.
millis
One of the best places to find one is right here. Look for a motor with the castings that you want, but with a blown head gasket, etc. I have had good luck finding stock blocks that only needed a hone to clean-up. In your Camaro the carb set-up would be a no brainer. If you find an LT1 with the 561 heads it should have intake part number 12552138. I would trade you the rods for that. I would much rather do a "no money" deal if possible. That way we both get junk that we want.
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From: Somerset Ky
Originally Posted by GIZMO
The LT1 block has a 4.00 bore and the L99 crank has a 3.00 stroke. Put those together and you have the same specs. as a 1967-69 Z28 302.
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From: Decatur, TN (N-W of Athens)
Originally Posted by LT1Z/28
so an lt1 block and L99 crank huh? Auesome
I'm really interested in how it turns out.
I always thought a 400 with a 327 crank would be interesting