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Getting 400+ HP from 350 LT1
I am dropping in a new motor due to a spun bearing on the stock one. While the motor is out I might as well "improve" it. The plan is listed below. What am I missing? I need to keep displacement stock to avoid a class change at the track. I'd like to push 400 hp at the crank.
1993 6-speed, stock fuel injection and computer. Off road only road race car, no emissions. Plan: Stock LT1 block and guts (transplanted from another car) Headers (eliminate cats and emissions) Borla cat-back (already on the car) Heads (edit - bought PP Stage III heads and matched intake) Roller rockers (edit - coming with the heads) Cam (edit - tuned to match the heads, coming together) Updated PROM to match cam and heads (edit - need suggestions) Moroso or Canton pan Accusump for safety edit - looking into electric water pump This combo seems to get me to about 370-380. What else am I going to need to reach 400 HP? I'm a little worried about intake mods because of the penalty. TIA |
Get your Al heads ported, find a cam that matches the heads flow, and a good set of headers, will get you 400+ hp at the crank.
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Are you trying to reach 400flywheel or rear wheel hp?
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What are the specs of the cam you are planning on running? Getting 400 FWHP from a 350 LT1 isn't very hard, but getting 400RWHP is a completely different story!!
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400 at the crank is no big deal, get some afr or ported lt4 heads, a decenct sized cam, long tubes, 52mm throttle body, and a ported intake, with a good tune with make easy 400, if you want 400rwp you will be hard pressed to do that with stock cubes, but nos or forced induction will get you there easy. I had an lt1 camaro that layed down 390rwp, but it wasn't realy a daily driver as the cam was pretty stout.
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With a stock short block I only made 360 rwhp. Thats about all I could get.
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You want to get 400 RWHP? Talk to this guy Lloyd Elliott about his LE2 package. Plenty of guys on the Camaro boards are running his setups and getting over 400 RWHP form a stock displacement LT1. I plan to use his services over the winter, but I'm only looking for 375-380 RWHP :D
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I would be satisfied with a 100 hp increase, so 400 at the flywheel.
Any cam suggestions? There are about 100 versions out there. Do I need a custom or is something off the shelf from Crane good enough? |
Originally Posted by ScaryFast
I would be satisfied with a 100 hp increase, so 400 at the flywheel.
Any cam suggestions? There are about 100 versions out there. Do I need a custom or is something off the shelf from Crane good enough? |
If your looking at a 400 flywheel hp car I would reccomend just a hotcam kit or simular. A hotcam kit typically produces 325-340rwhp depending on tranny and other mods. Its a really nice simple cam that has a muscle car lope and nice broad power band.
Cheap too, you can get it.. roller rockers, springs, retainers, for $550 if you look around. |
Recipe for 425 to 450 CRANK HP:
Corvette 350 LT1 with flattop pistons. (Stock components will work) LT1 Alum. Heads that flow over 260cfm/intake, 190 cfm/exhaust. (Pretty easy to achieve through CNC or hand porting by a pro) 1.75" Full length headers with dual 2.5" exhaust and hi-flow mufflers. Relatively large camshaft with at least 236 degrees of duration @ .050" and .550" to .585" lift, depending on the ported head's limit. (With no emissions and decent exhaust this can be a single pattern cam with 110 or 112 degree LSA) 52mm or larger throttle body with modified air filter assembly. 24lb to 30lb injectors, depending on who programs/tunes your PROM. .029" headgasket to get 10.75-11.0:1 compression, depending on final combustion chamber size after head porting/milling. MSD 6A or 'bigger' and a full-size coil for top end spark energy. Electric waterpump and an aluminum flywheel will also help the 'bottom line'. Comp Cams Pro Magnum Roller Rockers and measure for custom length pushrods. |
Originally Posted by ScaryFast
I am dropping in a new motor due to a spun bearing on the stock one. While the motor is out I might as well "improve" it. The plan is listed below. What am I missing? I need to keep displacement stock to avoid a class change at the track. I'd like to push 400 hp at the crank.
1993 6-speed, stock fuel injection and computer. Off road only, no emissions. Plan: Stock LT1 block and guts (transplanted from another car) Headers (eliminate cats and emissions) Borla cat-back (already on the car) Heads (precision porting GP?) Roller rockers Lingenfelter cam (tuned for more high end, possible rough idle) Updated PROM to match cam and heads Moroso or Canton pan Accusump for safety This combo seems to get me to about 370-380. What else am I going to need to reach 400 HP? I'm a little worried about intake mods because of the penalty. I have a set of iron heads from the donor engine, how well do they flow stock with a better cam? I assume a good set of aluminum heads will flow better and keep the weight down. TIA You are going where I am--modified LT1 for and put it on the road course. There aren't many. The dirty little secret I learned the hard way is that if you cam it, you have to use the LT4/Cloyes timing set to get a roller chain. Trouble is, they make that gear soft. What I think happened to me was that the new stock mechanical waterpump bearing seized and the marginal gear could not take the extra load, especially at higher rpm for a while on a course. Sent metal shards through engine. A word to the wise--use the old pump if it worked or else go electric. Electric means you'll run hotter--get an oil cooler. Old pump might leak eventually but bearing should be alright I guess. That my new one was bad might be a fluck, but what if it's not... |
500hp - thanks, that's exactly what I was looking for.
Sothpaw, can you elaborate on the timing chain? Do I need to replace this with a more robust one? Also, I was going to get a new water pump, but a new "stock replacement" water pump. |
I'm a fan of electric waterpumps.. gets rid of the weep hole that kills optisparks, gives you about 7rwhp, and easy to change out if theres a problem.
Also allows you to run a traditional SBC double roller timing set in the late model opti spark cars. I've never had a problem with over heating or running the slightest bit hotter with a electric waterpump. |
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Good stuff to know...
Originally Posted by Alvin
I'm a fan of electric waterpumps.. gets rid of the weep hole that kills optisparks, gives you about 7rwhp, and easy to change out if theres a problem.
Also allows you to run a traditional SBC double roller timing set in the late model opti spark cars. I've never had a problem with over heating or running the slightest bit hotter with a electric waterpump. |
I'm in excess of 400 CHP with just stage III LT1 heads, a Hotcam, headers, 1.6 RRs and not much more. I've got a little more compression than stock (11.3) but that's not a big gainer. Also the intake's ported, for what that's worth.
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I just ordered the PrecisionPorting Stage III heads, matched and coated intake and a custom cam from Bob. It's damn near impossible to find a cam with good lift off the shelf, nobody had anything much higher than .525 (and that's the LT4 hotcam). I should be set up nice with the custom.
I'll add the roller rockers, I'll discuss it with him tomorrow in more detail. Verdict is still out on the headers. Most people say 1 5/8 but I can't find anything definitive about it. EM is the only place with a set in stock and I'm on a time budget, so looks like I'll be going 1 3/4. I'll get the finger from some here but a hi-five from others... I need to find a PROM now. I plan to learn to do it myself, but I need something to get in there quickly so I can finish the racing season. Any suggestions? PCMforless? I don't want to spend too much since I'll be redoing it all when I have the time this winter. |
Originally Posted by Alvin
I'm a fan of electric waterpumps.. gets rid of the weep hole that kills optisparks, gives you about 7rwhp, and easy to change out if theres a problem.
Also allows you to run a traditional SBC double roller timing set in the late model opti spark cars. I've never had a problem with over heating or running the slightest bit hotter with a electric waterpump. Do you simply run a 12V line off of ignition, or do you set up a separate switch? I have an open switch on my panel (I think it's even labelled WP), I can just see myself forgetting to turn it on and heading out on the track... Hell, I've already killed the battery twice by forgetting to turn off the fuel pump. Idiot! |
Originally Posted by ScaryFast
It's damn near impossible to find a cam with good lift off the shelf, nobody had anything much higher than .525 (and that's the LT4 hotcam). I should be set up nice with the custom.
CompCams XFI Series made for LT1/4... 07-466-8 & 07-467-8 have .570/.565 lifts.. 07-468-8 has .584/579 lifts In stock at Summitracing Verdict is still out on the headers. Most people say 1 5/8 but I can't find anything definitive about it. EM is the only place with a set in stock and I'm on a time budget, so looks like I'll be going 1 3/4. I'll get the finger from some here but a hi-five from others... No comment, but I think I did all right with my EM on my LT4....I know I am stupid........so no comment....... . |
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