big horsepower small cube lsx
Im in the process of building a modern/old school front engine dragster which has some tricks that have not been done on one yet. The major one being a monoshock 4 link setup in the rear. ill have to get some pics for those who may be interested.
anyway. I was building the car to meet jr fuel regulations but decided that may want to venture away from that class and just build something for nostalgia meets and for fun. Initial plans were a small cubic inch SBC possibly a 301. 327 block with 283 crank. ive also looked into anything up to 400 block using a very short stroke crank. I dont really want anything over 320-330 CI. After talking to a friend and engine builder of 20+ years he feels that one of these motor combo's could turn 11k rpm. Id like to be a little more conservative and say 9500 to 10k.
So here the question comes. Do you guys think the same would be possible with an LSX. I would love an aluminum block due to the major weight savings. As far as ive seen what im looking for is another 1k rpm further then whats around. obviously massive flowing heads and intake are needed aswell as a very large cam. Motor will most likely be mechanical stack injection on alcohol with a 10% nitromethane cut. I have looked at the 4.8 engines but a little more on the bore and a little less stroke would be better i believe, also no alum block. I know this motor would have a narrow powerband but again this would be in a 1400lb car with a stall in the 7k rpm range into a powerglide trans.
let me know what you guys are thinking.. good, bad, indifferent. hell maybe someone has already gone crazy with this and i just havent found it!!
LSx would be cool in that combo.
10k is definately possible with a short stroke motor. 11 would be pushing it. He had run a 301 setup in a 1st gen camaro stick car where they would launch in the 8k rpm range and shift at 9600. an 11k rpm tach with recall proves it. hell look at nascar turning the rpm they do for hours! were only talking a few seconds here.
10k is definately possible with a short stroke motor. 11 would be pushing it. He had run a 301 setup in a 1st gen camaro stick car where they would launch in the 8k rpm range and shift at 9600. an 11k rpm tach with recall proves it. hell look at nascar turning the rpm they do for hours! were only talking a few seconds here.
1. What kind of flywheel gasoline NA horsepower do you need from the 320 cubes? 600? 650? 675?
2. How much money can you spend? 9000+ is going to get very costly, even with no more hp than 7500-8000....probably less.
3. Is this more about rpm than actual power and drag strip performance? I hope not.
FWIW, would 8.70 @150s mph meet your goals? There is a rear engine ~1500# pump gas rail running a 6.0L LS truck engine with a hydraulic roller spinning 7500+ using stock LS lifters (not the Caddy race lifters) which runs those times.
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Why would someone design an engine to run a certain RPM. 99.9999% of normal people build per their budget or to get a minimum HP/size to compete in a certain class. If you need to run small small inch's, than you will have to spin it more.
As you mentioned, you have looked at several combo's. You have learned, big bore, short stroke, will give you more RPM safely.
10-11K is probably no big deal to actually do, they have 10K BBC's. The issue is maintenance, longevity, reliability.
Springs take a beating at those levels. TI valve's are expensive. Top of line push rods, shaft rockers, lighten rods ect.
To each his own & it's your car & money, but most people are going to ?? why you want a 301".
Especially when you can have more power, cheaper, more reliability with a 400-412 type engine. Good luck.
.
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1. What kind of flywheel gasoline NA horsepower do you need from the 320 cubes? 600? 650? 675?
2. How much money can you spend? 9000+ is going to get very costly, even with no more hp than 7500-8000....probably less.
3. Is this more about rpm than actual power and drag strip performance? I hope not.
FWIW, would 8.70 @150s mph meet your goals? There is a rear engine ~1500# pump gas rail running a 6.0L LS truck engine with a hydraulic roller spinning 7500+ using stock LS lifters (not the Caddy race lifters) which runs those times.
1. was shooting for 700hp on alcohol. minimal gains over race gas.
2. I dont have any sort of budget set yet as I am just tossing up ideas on what to use. I would need custom crank, rods, pistons, heads, cam, valve springs ect. which would start adding up quickly but other things like girdle, larger head studs, anything to do with machining or modding already existing parts i can do.
3. It is not all about the rpm, i would like a very good performing car. I just want to try to do it on a small cubic inch motor with no power adders and on that playing field you have to step it up in some other way.
as far as how fast that comes down to the hp and weight both of which i dont know now. 700hp in 1400lbs should go around 7.50 at 180 chassis cert will be 6.30 which it wont ever see
it CAN be done.
it WILL be EXPENSIVE.
...and you'll get good and rebuilding it, really fast.
1. was shooting for 700hp on alcohol. minimal gains over race gas.
2. I dont have any sort of budget set yet as I am just tossing up ideas on what to use. I would need custom crank, rods, pistons, heads, cam, valve springs ect. which would start adding up quickly but other things like girdle, larger head studs, anything to do with machining or modding already existing parts i can do.
3. It is not all about the rpm, i would like a very good performing car. I just want to try to do it on a small cubic inch motor with no power adders and on that playing field you have to step it up in some other way.
as far as how fast that comes down to the hp and weight both of which i dont know now. 700hp in 1400lbs should go around 7.50 at 180 chassis cert will be 6.30 which it wont ever see
It's not a DIY project, IMO.

Chris.
Eagle makes a 6.385 BBC rod cut for 2.100 journals which I'd like to try with 1.13 comp height pistons (for 383 or 400 w/ 6" rods). Off the shelf components for the win.
Last edited by The Dark Side of Wil; Jul 15, 2008 at 12:43 PM.
I initially looked into the smaller cubic inch realm when i started building the car for use in nostalgia dragster class like the jr fuel a/b. in this class you need 3.5lbs per cubic inch so the less cubes the lighter the car. there is a minimum though. max cube is also 410. One last thing is it has to be iron block sbc, sbf, or hemi with factory style iron heads. must run alcohol and must run stack injection, no collector headers. well the lsx definately pushes us out of this category but i would like to still stick with the same concept on weight and other things. take a look at some of the junior fuel A cars. they are well into the 6's with a little old small block and no power adders. if you look around thats not far off the tail from the nostalgia top fuel guys!







