I had an idea for an engine I might want to build for my f-body, What if i took the stock engine, Bore it 20 over and give it a 3.250 stroke, this will give me a total displacement right at 330 cubic inches, now why destroke like that? Well if I toss on a good set of ported heads (like LE1s) and match the camshaft up right I could have a monster of an engine, itl'l just have to rev a little higher. If I tighten up the deck clearance a little to .015, add a 5.85" rod and keep the stock 9.025 deck clearance I will be able to use a piston with a compression height up to 1.535" (which can be reduced by dropping off the deck height if I cant find a piston that big or it is determined to be too heavy a piston) This will allow me to have a high reving motor that is perfectly happy to rev to 7000 rpm and higher with a good ring pack so it will be able to take the abuse of a little nitrous (maybe a 100 to 200 shot of nitrous)

 

Does the adage "there's no replacement for displacement" ring a bell?

 

It will take more than 7000 to make the little one preform.

 

I like your creative thinking. It does seem to me, however, that there's plenty of guys on this message board who have built their 'standard displacement' LT1s to live easily at 7000 RPMs... without giving up that 20 cubic inches.

 

I like the idea, but the simple fact is you can go with a nicely built 355 or torquey 383 that will be much better in terms of power/driveability while keeping the revs under 6200rpm's. If your throwing around an idea to destroke an LT1, why not try and build a nice 4.3 LT1. I believe you can interchange parts easily and then drop it into a sleeper car no problem. there was talk of a 4.3 LT1 with a roots type blower floating around, i bet that'd be fun. my .02

 

Plus if you want to spin over 7000rpms you can't use the stock computer.

 

That would be a fine idea for a dragster in comp eliminator to take advantage of the weight savings, but these cars are heavy and the stock computers only have a limited RPM range. 350-380+ inches will serve you better.

 

I forgot about the stock pcms limiter, well hopefully with the job im picking up soon il'l be able to afford aftermarket pcm if i do go this route, the idea behind this is theoretically this engine would hold up to more power than a similarly build 383 or 355, due to having a better ring pack and not having to worry about interferance as much with the connecting rods ( I could use a nice set of 5.85" H-beams and they would fit in nicely without requiring me to to use a shortened/weakened piston) Quench also becomes a game of how much do i want to deck the block instead of how much piston can i fit without going further than just a light kiss to the head.

 

Whatever you're smokin, how about sharing?

 

Displacement may make more torque but it ain't what makes power. Properly setup theres no reason this destroked motor can't make just as much if not more power than a 383 with similar heads. plus, If you look closely at the specs im giving, youl'l realize its not actualy a 330 i'm building, but a 327 at .020 over. It's also dead on 1.8:1 rod-stroke ratio, This gives the pistons a low maximum acceleration but high overall velocity at high rpms.

 

Build it and they will come.

 

Sounds like you have really thought this out, but why try to make power with a smaller destroked motor. All I'm saying is apply all of your thinking to a 383 and you will make more power than the adverage guy with a stroker motor. I'm not trying to change your mind for you or anything like that.

Good luck with whatever you decide to do

 

Yes it does. You can't argue with the fact that you can build a mild BBC which would rivlal the **** out of an all out destroked engine. If you don't have torque you will not produce agressive power unless you rev and gear the snot out of it... and there really is no benefit to that unless you like a screaming banshee for an engine with little to no street manners.

 

I considered it as a fun project. I was gonna do a 302 LT1, using a 3" crank from the baby LT1. I was gonna top it off with some ported heads, GM847 and a single plane for a top end-only motor. Never did because of the PCM limitations. As soon as I overcome those, I'd be spinnin the crank at a more than desirable speed for a factory offering. So I would be knee deep in a rotating assembly, for what?

I decided to keep the stock cubes. Now that I've done my share of strokers, I'm building a bigger motor adapted to drop in place of the LT1. Bore and RPM generally contribute to HP and stroke and velocity to torque, and with a properly built stroker motor, you can have both. I can understand if you wanted a motor merely to operate between 3500-8500, but what's the fun in that? You cant use it on the street (much) haha

 

double post...