383 vs. LT4

FireFox05 · #1 06-14-2005, 01:53 AM

Well, over the past while I have been doing more serious in depth research and have found that my LS1 plans probably won't come through. Sad for me, but oh well.

In looking however, I have found it to be much more likly to get around a '94-'95 LT1, and have been researching power adders for that.

I think the two starting blocks, besides basics such as intake and exhuast, etc. are either a 383 Stroker or the LT4 conversion.

Advice on which road to pursue? Cost vs performance plus drivability?

Thanks.

FireFox05 · #2 06-14-2005, 02:00 AM

Here the two I found:

Summit, LT4
http://store.summitracing.com/defaul...=NAL-GMP3287-1

RPMmachine, stroker
http://www.rpmmachine.com/350-chevy-...roker-sb.shtml

MPG is also a consideration.

89IROC&RS · #3 06-14-2005, 02:12 AM

personally, i dont know what research you found that makes you think the LT1 based engine are a better starting point than the LS1 based engines. I would much rather work from the newer LS1 engines to make power. there are compareable mods for the LS1 to the LT1 mods you are looking at. But the LS1 will be more reliable.

FireFox05 · #4 06-14-2005, 02:16 AM

Age and price mostly. Same parts, but $10,000 cheaper car to start from. Plus, I am not making a drag car, at least not right away. And lastly... I guess I just like the original 4th gen look a little better.

FireFox05 · #5 06-14-2005, 11:19 AM

Well I found an awesome head and cam guy, his name is Lloyd Elliot.

Check this out, tell me what you think:http://eportworks.com/LT1LE2.htm

Only thing I don't know, what are 1 3/4 LT's? I get the fact you need the intake system, TB and whatnot, and exhaust.....

FireFox05 · #6 06-14-2005, 11:38 AM

Oh, it means Long Tubes right?

89IROC&RS · #7 06-14-2005, 07:18 PM

you get a gold star kid

FireFox05 · #8 06-15-2005, 01:36 AM

Hahaha. Thanks, I think.

So does anyone have any advice or ideas?

LT1MAN · #9 06-15-2005, 09:57 AM

Quote:

Originally Posted by FireFox05

I just like the original 4th gen look a little better.

right on man!!!

FireFox05 · #10 06-15-2005, 12:10 PM

MMonnier2302 · #11 06-15-2005, 01:12 PM

I think the first stroker crank isnt for an LT1, i was also interested in a 383 crank and have already done alot of research, here was a link i used
http://www.speedomotive.com/LT-1%20C...0383%20KIT.htm

but you can also try golen for the shortblock strokers, they also sell a 480hp 520lb longblock, but as far as just the crank and accesories, above is the better plan.

DVS LT1 · #12 06-20-2005, 02:02 PM

Work on the heads first, then stroke the motor. If its a matter of dollars and cents and you can only do one route or the other I'd say sink your money into the heads.

I wouldn't exactly settle on the LT4 heads though - those castings with 2.00" intake valve flow around 245 cfm at .500 lift. I'd pick up a set of bare LT4 castings and go for a port & polish job with possibly a 2.02" intake valve - or port the stock LT1 castings and throw in something like a 2.055" valve.

FireFox05 · #13 06-20-2005, 06:34 PM

Do you think it would be better to get a port from eportworks.com on LT4 heads or the stock heads? I'd really like doign it on the stockers, then I wouldn't have to buy those LT4s just to have them polished and worked.

DVS LT1 · #14 06-20-2005, 08:03 PM

Never heard of eportworks...

The LT4 castings are serious toys. Those suckers can be made to outflow any LT1 casting. I hate hearing it myself but it all depends on what you what to do. Some guys spend thousands on fully CNC ported & polished AFR heads with 2.08" or 2.10" valves just to turn them right over to a performance shop and take off even more material, put in better valves, etc... How much HP do you want to make?

You're obviously paying less by working on stock LT1 castings. Your basic budget setup is porting them out and going with a 2.00" valve - the stock LT1 valve seats can be made to accept that size. Anything bigger and the seats have to be replaced and additional porting around the pockets has to happen. I think most shops get about 260 cfm between .500-.550 lift from ported LT1 castings with a 2.00" valve (depends on valve job).

I saw places years ago that offered this type of work for under $1500 USD (CNC job), plus extra stuff like a cam or something. Would probably be a lot cheaper now. Figure it out - how much would complete LT4 castings cost you, then add in just a port and valve job on the existing/stock 2.00" valves (those sodium filled intake valves are actually pretty decent, and lighter than stock LT1).

One thing thats becoming more popular these days are guys taking the LS1 style valvetrain components and using them on the LT1/4 Gen II heads (bee-hive springs, lightweight retainers, etc...) You bolt up a set of heads that flow 280, 290+ cfm with an ultalight valvetrain on top and that engine will be able to accelerate to 7000 RPM in no time.

Some guys live by cubic inches or big cams, and others swear by hi flowing heads. Its volumetric efficiency that the latter guys are talking about. Fact is by increasing the stroke you decrease the RPM acceleration of the engine. I personally think a stroker project is a waste if you plan on using stock heads - you'll have a big bad motor making loads of torque that will be completely starved for air at the top end. You hear about guys like that putting up big numbers on a dyno and then running slow ass times at the track.

Do the heads first, then drop in the crank.

89IROC&RS · #15 06-21-2005, 12:15 AM

cubes are nice, but i guess im one of those efficiency guys, ive always felt power was made by the cam and the heads, extra cubes are just an easy way to put more air and fuel in the engine. so ill agree with DVS LT1 that you should do the heads and cam first, and then do the stroker.

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