LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Using 18* (or 15*) SBC heads on a LT1

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Old 06-29-2010, 01:24 PM
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Default Using 18* (or 15*) SBC heads on a LT1

Besides using 18 degree specific pistons in the short block and 18 degree specific intake mainfold and converting over to reverse cooling, what else is required in using these heads in a LTx engine???

Do regular SBC/LTx headers still match up??

Can you still use regular HR lifter and roller rocker arms(in other words a conventional SBC valvetrain)??

Do you think flow number that these heads produce N/A makes the conversion worth it for high performance street???

I am thinking of going this route for my 383 LTx stroker build on my '95 Caprice instead of the usual 23 degree head Advanced Induction or Lloyd Elliot route that everyone seems to go.

One reason in prompting me in going this way is from an article in the February, 2009 online issue of Hot Rod magazine, Lingenfelter Performance Engineering built a 420ci small-block engine with a Bow-Tie block, a Callies 3.875-inch stroker crank, Oliver rods, and a Comp Cams roller. With 11.0:1 compression, 18-degree Chevy heads, and a Bow-Tie single-plane intake manifold fitted with EFI, this big-inch Mouse produced a stout 623 horsepower at just 6300 rpm.
Old 06-29-2010, 02:03 PM
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It can be done....just as with converting SB2/2.2 nascar heads.....just gonna cost you a little bit of $$$
Old 06-29-2010, 02:10 PM
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Im not for sure but, wouldnt the exhaust port location be a little lower. low enough that custom made headers would be required?
Old 06-29-2010, 02:25 PM
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headers would be required to the best of my knowledge the face angle changes as well to the flange would have to be angled to match.....so a custom set would be the best bet IMO
Old 06-29-2010, 02:32 PM
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i figured that for sure. i would get some afr210s ported by LE and say screw the conversion. my .02$
Old 06-29-2010, 02:39 PM
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I'm all for being different, but unless you are willing to put things on hold for the build, or you're independently wealthy, I would consider alternatives....
Old 06-29-2010, 02:50 PM
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You need

Pistons

Headers(full custom set)

Intake

Offset lifters

Rockers.

Its not worth it IMO. Too expensive for what you get to DO IT RIGHT.

Look up a guy on here N20DAVE, he did this already. Made 700 hp all motor.

With a 12to1 compression 396 and a good set of 23* heads, single plane you can make 600+
Old 06-29-2010, 02:51 PM
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^^^^^^^^^^
Old 06-29-2010, 05:41 PM
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Guys, don't waste your keystrokes. This guys spams all the LTx forums with nothing but bench racing.
Old 06-30-2010, 11:28 AM
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Originally Posted by 96capricemgr
This guys spams all the LTx forums with nothing but bench racing.
This is a very technical skill.
Old 07-11-2010, 02:51 PM
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Default Don't stop anyone from acquiring wisdom and knowledge

Originally Posted by 96capricemgr
Guys, don't waste your keystrokes. This guys spams all the LTx forums with nothing but bench racing.
Listen Dwayne, I really respect what you have done with your AI heads and stock short block in your Caprice. But if I am going to spend at al least 5 to 10K of my hard earned dollars on a rebuild your are damn skippy I'm going to ask questions of anyone who is knowledgeable and will answer back. Only fools don't ask questions or just take the first answer they hear. As the wrter of Proverbs said "There is safety in a multitude of counselers"
Old 07-11-2010, 02:57 PM
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Default You gotta point there

Originally Posted by FASTFATBOY


With a 12to1 compression 396 and a good set of 23* heads, single plane you can make 600+
Ya know know, I'm kinda leaning towards that way. But Fastfatboy, is those 600+ FWHP be completely streetable for use in Daily Driver??
Old 07-11-2010, 03:36 PM
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Originally Posted by B'klyn9C1
Ya know know, I'm kinda leaning towards that way. But Fastfatboy, is those 600+ FWHP be completely streetable for use in Daily Driver??
I plan to street drive in that power range using 23* heads and an HR...but "streetable" depends on who you ask. In my case it wont be a DD because of gas mileage(4k stall and 4.10s), but will be driven 2-3 times a week.

Honestly 5-10k probably wont be enough cash though. Dont forget you will need a lot of supporting mods to make a combo that aggressive work, and you cant skimp on parts if you want it reliable.
Old 07-11-2010, 04:17 PM
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Originally Posted by Puck
I plan to street drive in that power range using 23* heads and an HR...but "streetable" depends on who you ask. In my case it wont be a DD because of gas mileage(4k stall and 4.10s), but will be driven 2-3 times a week.

Honestly 5-10k probably wont be enough cash though. Dont forget you will need a lot of supporting mods to make a combo that aggressive work, and you cant skimp on parts if you want it reliable.
My DD is '95 Caprice 9C1 now has 3.73's and will have 2800 stall Vig or Yank when its done. Full long tube from Clear Image Automotive w/cats and like to run an EFI Connection 24X setup w/a Victor E manifold and 4 BBL TB.

Yeah you are right about not skimping on the support mods.
Old 07-11-2010, 04:24 PM
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Originally Posted by B'klyn9C1
Listen Dwayne, I really respect what you have done with your AI heads and stock short block in your Caprice. But if I am going to spend at al least 5 to 10K of my hard earned dollars on a rebuild your are damn skippy I'm going to ask questions of anyone who is knowledgeable and will answer back. Only fools don't ask questions or just take the first answer they hear. As the wrter of Proverbs said "There is safety in a multitude of counselers"

I used to believe that too, but then I got a clue, and the car got faster.
Old 07-11-2010, 05:09 PM
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If your asking about that kind of set up, it's really not for you, no offense intended. But this would be like posting in the drag racing section of ORSCA and asking what I need to build a competitive Limited street car. This would be a really involved set up. Finding a machine shop competent to tackle a project like this would be a challenge in it self, the guys that can, I hope you like waiting. In a street car it's just not worth it, stick with a 23* head and use a power adder. A 600rwhp all motor any thing wont be a daily driver or any where close to it. Also $5-10K isn't realistic, I would budget closer to $20K all said and done to do it right.
Old 07-11-2010, 05:24 PM
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if your looking to daily drive a 600hp n/a engine with swapped heads, you are out of your mind. if you have the money to build that, you should have the money to get yourself a decent daily driver, too.
Old 07-12-2010, 11:13 AM
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Originally Posted by BizZzatch350
If your asking about that kind of set up, it's really not for you, no offense intended. But this would be like posting in the drag racing section of ORSCA and asking what I need to build a competitive Limited street car. This would be a really involved set up. Finding a machine shop competent to tackle a project like this would be a challenge in it self, the guys that can, I hope you like waiting. In a street car it's just not worth it, stick with a 23* head and use a power adder. A 600rwhp all motor any thing wont be a daily driver or any where close to it. Also $5-10K isn't realistic, I would budget closer to $20K all said and done to do it right.
I wasn't talking about RWHP but 600 FWHP. If you go up to the beginning of my thread you'll see about a LPE big inch SBC making 600+FWHP with only 11:1 static compression ratio. A streetable CR would you say? Granted this is with an aftermarket block w/a 4.100+" bore and such a deal maybe just beyond the limits of LTx block. but you see it can be done.
Old 07-12-2010, 11:59 AM
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600 flywheel isnt that hard. i believe u can do it with a stock ported manifold. thats what ill be trying, atleast. no point in spending all that money converting heads and all the hard to find supporting **** when u can do it with lt1 specific stuff
Old 07-12-2010, 12:35 PM
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there are plenty of 600+ FWHP LSx cars prowling the streets of chi-town. 600 FWHP isn't much more then 450 RWHP.....give or take. Finding a wrecked running LSx powered car would be a cheaper and faster way to get to the 600 hp mark within your budget......


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