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

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Old Aug 4, 2011 | 02:04 PM
  #21  
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Originally Posted by Puck
You can't just make any power at any RPMs by changing the cam...a smallblock wants REVS to make big numbers.

I don't see 750hp being made at 7k, even on a 408, no matter what parts you use.
This I understand, and that's not what I was implying. What I'm trying to say is that I "may" not have to spin it as high as everyone is implying due to the size. As we all can plainly see, all things being the same, a 383 will make the same hp at a lower rpm than a 350. All I'm saying is that just because a 355 makes 750 hp at 7500 RPM, in theory a 408 will make the same hp at a lower RPM, but if taken to 7500 RPM it would make more. I suppose this is reaching more to engine theory than setup.

Originally Posted by quik95lt1
have you any actual experience with an 18* platform on a sbc shortblock??
Yes, granted it's been a few years and not only has technology advanced, and parts have gotten a lot better.

Originally Posted by YSILT1
Like everyone else has said. I would use a Callies Crank and there H Beam Rods.

I would at least talk with the guys over at TEA. I love the heads and Intake setup they made for me. They really know there stuff.

I have heard good things from the new Brodrix.
Callies doesn't make a 4" stroke 1pc rear main seal for the gen I or Gen II engine. Now I do like their products, but I'd rather not spend $2000 (quoted from K1, a division of weisco) to get a one off crank should something happen. On the other hand I really like the Callies Magnum XL line, especially because of their weight....34-47 lbs is friggin light! Maybe I'll just bite the bullet since everything else on the damn thing will be custom, I might as well just dump some more coin and really not worry about the RPM factor.....
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Old Aug 4, 2011 | 02:07 PM
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Originally Posted by YSILT1
Like everyone else has said. I would use a Callies Crank and there H Beam Rods.

I would at least talk with the guys over at TEA. I love the heads and Intake setup they made for me. They really know there stuff.

I have heard good things from the new Brodrix.

with that much stroke and plans of 7500rpm+ i would try to reduce the bob weight of the rotating assembly as much as possible...........id look into an ibeam/billet style rod vs. the hbeam design.......the callies compstar I beams are a pretty nice piece......
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Old Aug 4, 2011 | 02:12 PM
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Originally Posted by duh
So the wife told me I can start building an engine....it's going to be slow due to costs of the parts, but I want some opinions.

Block is a stock LT1 and going to have splayed caps on all 5 mains
Eagle 4" stroke crank for a 1pc rear main
H-beam 5.85" rods - brand undetermined
custom 4.030" 18* pistons - brand undetermined
Brodix 18X CNC ported heads
Solid roller - specs to be determined
7/16" 1.6:1 roller rockers - brand undetermined
3/8" pushrods
rocker girdle

I'm thinking total seal rings, and coated bearings.

I'm going to have to use a single plane intake as it would probably hurt me to use a modified LTx intake, so that will most likely be a Brodix intake converted for injection with a 4bbl throttle body. I'm planning on going with the 24x conversion and most likely a th350/400 swap since the little 4l60 in there won't last long. The goal is 750+ at the flywheel and then maybe some spray on it for when I get bored. Believe it of not this is going into a primarily street driven car, that will see occasional track time. Now before everyone says you won't like it on the street, I'm the type of guy that doesn't mind adjusting valves every oil change and changing springs every couple of years. And on top of that, I'm going to convert over to a hydra-boost system since I'm sure the vacuum signal will be near nothing. Plus I only drive my car a couple miles a day, unless something weird happens, so my street driving is far different from most peoples.

Go ahead and nit pick and let me know what you guys think. Please don't bash the fact that it's a 408. I'm looking for constructive criticism.
couple of other things i noticed..........
those heads will need to be converted to run on the lt1 block.......
also ditch the 7/16" rocker idea and run a shaft setup that motor will be no place to be screwing around with a stud rocker.......
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Old Aug 4, 2011 | 02:15 PM
  #24  
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Originally Posted by quik95lt1
couple of other things i noticed..........
those heads will need to be converted to run on the lt1 block.......
also ditch the 7/16" rocker idea and run a shaft setup that motor will be no place to be screwing around with a stud rocker.......
The heads will be converted....believe it or not last I checked Brodix will do it for an extra $400 at their facility.

And I guess I should change it in the first post, but Shaft mounts will be used...
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Old Aug 4, 2011 | 03:00 PM
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With undertakings such as this what is the desire you guys have in staying NA? RPM?
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Old Aug 4, 2011 | 04:13 PM
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Originally Posted by LSWHO
With undertakings such as this what is the desire you guys have in staying NA? RPM?
NA is more fun .
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Old Aug 4, 2011 | 05:56 PM
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Originally Posted by quik95lt1
yea but its always nice to start your burnouts at a 40mph roll
I'm not going to argue with that.
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Old Aug 4, 2011 | 05:56 PM
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Just in the last year a friend had a 750ish HP 40X ci Gen 1 built off a Dart block, wildly custom 23degree heads and intake. I have ideas about what little bits of it cost and you have no idea what you are getting into. I don't know exact numbers because he is not a dyno racer but I know it makes near 750flywheel and I know it goes to 8500rpm. I also know he has a couple sets of lifters so they can be swapped for routine rebuild, betting the custom shaft mounts get rebuilt at least once a year, believe they are only looking at 2000miles out of springs and the cam was tweaked on the spintron for low pressure. He spent more on valves than people here want to spend on heads/cam complete valvetrain and I believe he got the valves near wholesale.

I don't have direct experience but watching a friend go through exactly this and watching his growing pains and having heard prices on a few things I can say conclusively you have no idea what you are in for.

The builder he had in charge of this build is a real professional, like Cup and ProStock stuff.

18 degree will make it a little easier for you but cost, rpm and upkeep are still going to be beyond what you expect and you will need TOP notch support from a very good shop, not an average one and not just a shop with a good internet reputation.
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Old Aug 4, 2011 | 06:16 PM
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If I was building a 750+hp engine this is pretty much the last place I would go for advice on it...
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Old Aug 4, 2011 | 06:20 PM
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Also a good point.
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Old Aug 4, 2011 | 07:05 PM
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Originally Posted by speed_demon24
If I was building a 750+hp engine this is pretty much the last place I would go for advice on it...
Best advice yet.
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Old Aug 4, 2011 | 09:14 PM
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Trust in the fact that the machine shop I use is very good, not even a well known shop on the internet. They are local and build wild stuff that wins. Infact they did a friends 650 hp 406 a few years ago. The true intent is not the rpm range, more the power....too bad it takes rpm to get there. And the real reason for staying n/a comes more from personal taste. Not really a fan of poweradders.
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Old Aug 4, 2011 | 09:32 PM
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Originally Posted by duh
And the real reason for staying n/a comes more from personal taste. Not really a fan of poweradders.
I get that. Out of curiosity have you ever owned a boosted car?
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Old Aug 4, 2011 | 09:50 PM
  #34  
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doesn't seem like you really want criticism, but I'll throw my hat in the ring anyway.
I understand the point to be different by going 408, but if everyone builds a 383 or 396 its probably for a good reason, why mess with a good thing?
the 4" stroke is gonna make you cut the hell out of the oil pan rails on the block if you use a H beam rod and its gonna put a ton of stress on the walls at high rpm.
stud mount rocker arms? a joke after you break the 500hp mark go with T&D shafts or Jesel
Knowing how good ppl are getting 23* heads to flow now days I would save some cash and go with those.
Iam not trying to build your engine for you, this is just my opinion
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Old Aug 4, 2011 | 09:51 PM
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If only there was a 15-12 degree heads from the factory that also made a six bolt block with an aftermarket to actually make this power level feasible. Just kidding.

Anyway, you are pretty much describing a Busch Grand National engine. Do a little digging and you will be able to find parts and info on these SB2.2's

My dad and uncle used these on their late model stock cars. And would make upwards of 850hp. These are NOT cheap. And there are WAY better ways to do this, but if you are dedicated to the SB2/LT1 then so be it. Just remember, you are pretty much quadrupling the price for entry by going the Gen2 route rather then the Gen3.
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Old Aug 5, 2011 | 07:28 AM
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Originally Posted by 96capricemgr
Just in the last year a friend had a 750ish HP 40X ci Gen 1 built off a Dart block, wildly custom 23degree heads and intake. I have ideas about what little bits of it cost and you have no idea what you are getting into. I don't know exact numbers because he is not a dyno racer but I know it makes near 750flywheel and I know it goes to 8500rpm. I also know he has a couple sets of lifters so they can be swapped for routine rebuild, betting the custom shaft mounts get rebuilt at least once a year, believe they are only looking at 2000miles out of springs and the cam was tweaked on the spintron for low pressure. He spent more on valves than people here want to spend on heads/cam complete valvetrain and I believe he got the valves near wholesale.

I don't have direct experience but watching a friend go through exactly this and watching his growing pains and having heard prices on a few things I can say conclusively you have no idea what you are in for.

The builder he had in charge of this build is a real professional, like Cup and ProStock stuff.

18 degree will make it a little easier for you but cost, rpm and upkeep are still going to be beyond what you expect and you will need TOP notch support from a very good shop, not an average one and not just a shop with a good internet reputation.
by no means am i making 750fwhp......but im prob approaching the 700 range..........and i've got alot of $$ and time and reasearch in the car.......and keep in mind even with a very well setup 23* TFS head im still revving the car 8000 rpm+.......

if 750 hp NA was attainable under 7000rpm you wouldn't see cup cars running around at 9500+rpm...........you WILL have to rev the motor to make that power.......done end of story......

Originally Posted by speed_demon24
If I was building a 750+hp engine this is pretty much the last place I would go for advice on it...
best advice ive heard in this thread yet........

Originally Posted by JakeSS/Z28
doesn't seem like you really want criticism, but I'll throw my hat in the ring anyway.
I understand the point to be different by going 408, but if everyone builds a 383 or 396 its probably for a good reason, why mess with a good thing?
the 4" stroke is gonna make you cut the hell out of the oil pan rails on the block if you use a H beam rod and its gonna put a ton of stress on the walls at high rpm.
stud mount rocker arms? a joke after you break the 500hp mark go with T&D shafts or Jesel
Knowing how good ppl are getting 23* heads to flow now days I would save some cash and go with those.
Iam not trying to build your engine for you, this is just my opinion
^rocker arms have absolutly 0 to do with the hp level you are making........has completley to do with the lobe profile of the cam and the spring pressure you are running...........

also its apparent that nobody has even read my advice about large stroke/high rpm issues in the stock blocks.........
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Old Aug 5, 2011 | 07:49 AM
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Originally Posted by RamAir95TA
So why even ask for constructive criticism if you aren't going to listen to anyone's suggestions?
Originally Posted by quik95lt1

also its apparent that nobody has even read my advice about large stroke/high rpm issues in the stock blocks.........
Seems to be the going trend in this thread...
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Old Aug 5, 2011 | 07:52 AM
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The stock block long stoke is a valid point. Since my friend used a Dart SHP gen 1 block he only needs a 3.75 stroke to get 400 cubes. A quarter inch more stroke is a LOT of extra stress on stuff.
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Old Aug 5, 2011 | 08:10 AM
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Originally Posted by 96capricemgr
The stock block long stoke is a valid point. Since my friend used a Dart SHP gen 1 block he only needs a 3.75 stroke to get 400 cubes. A quarter inch more stroke is a LOT of extra stress on stuff.
exactly the stress grows exponentially with rpm and stroke..........many sieze to understand this........
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Old Aug 5, 2011 | 09:01 AM
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So basically I'm being told that if I want to run an 18* setup it would be better to destroke the engine and run a 302 and spin to 10K to get my hp goals....I wouldn't mind that too much either...lol
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