Well, since I got shafted on my motor(s)(the LT1 and LS1), Im stuck. I dont know whether to go with the 383 project or make a 355. Has anybody on here got the Scroggin Dickey Vortec TPI manifold?? I thought about going with that manifold and Vortec heads on a 355 but $400 for the manifold and $700 for the heads almost justifies some AFR 190's......right? Which way would be better? A 355 with AFR 190's, AZSM LTR's, hogged out plenum, etc....OR....a 383 with an LT1 intake, and AFR 210cc's?????? SOrry to be soo much trouble on here. I honestly wouldnt have posted my last post had I known the jerk wouldnt honer his false ad.....Advice on the 355/383???? Which would be better in my 91 Z?

 

Personally, I am partial to the 383.

 

Uh,, lets see.

Bigger engine, better heads, and an intake more suited for bigger engines with better flowing heads that's a tough one. Compared to a smaller engine with less flowing heads with an intake better suited for smaller engines with lesser flowing heads. Man,, I don't know. Maybe the 383,, no,,, the 355,, no,,, wait,,,,, the 383 - yep,,, my vote's for the 383.

Sorry guy,,, I couldn't resist. Not that this was one of your choices,, but a flat top 406 (stock block, crank, and rods) with the race ready 227's and a converted LT1 (provided no problems sealing on the 227s) would be a serious bang for the buck build.

 

Yeah, DUH I was just curious......Will the LT1 intake seal properly on the heads though?? I guess I made a good decision considering I already have a 383 bottom end By the way, I heard something about the cam COMP recommended to me(.560lift, 236-244 dur at .050, 114lsa) My machinist said I dont want to go over a .490 lift with a lockup torque converter.....He said the rpm harmonics of the valvetrain would destroy the converter when it is in lockup mode?? Anybody ever heard of this? It makes sense, but what about the cam? OR should I put my T56 back in and say f**k it?

 

Find another machinist. Or pray he at least knows how to operate the equipment - lol. IMHO - 114 spread is too wide for a naturally aspirated big cube engine - you're better off for a street kicker keeping the duration smaller and going with a tighter spread - especially if you're going to burn your own chips eventually. Be sure to run "matching" / recommended springs for what ever cam you run.

 

So you think 112 would be ok? Ive never heard that either, but he builds alot of exotic stuff($50K motors, etc) so I assumed he knows what he's talking about.....Oh well

 

Think about it this way...

There is NO substitute for cubic inches. On top of that, stroker motors are monsters for torque. If you are really tied on power, but wanna remain small block, search around and build a Chevy 400. Don't dick with stroking.

Stroking a motor makes it more of a specialty motor. When something breaks on a 383, itll take time and money to fix. When something breaks on a 350, most are back at the track withing the next week. Something to consider if you beat the hell outta the motor. Also, It'll take more than just a machined crank to make a 383. You still have to externally balance it and get new pistons.

A 400SBC will out do any 383 if done right. Take a good look. What's the difference between a 383 and a 400?

Same crank.... more meat on the 400 to play with. I'd say ditch the project and go SBC 400.


~Cory

 

Youre right....WS6...Im thinking of going with a 383 though still since thats what I have for now..But hey, If it breaks thats a good reason to build a 400.. Im thinking 76cc isnt too big with flat-tops, it should be around 9.5:1 to 10:1 depending. The way the heads flow(246cc between .400-.500lift) I wont need a huge cam. Im gonna go with a carb though(650 Holley) with the venturies tuned and metered right, etc. and probably a Edelbrock dual plane intake......IT should be a monster in HP and Torque.

 

Maybe the joke's on me. I've heard people say the harmonics from the valvetrain will detroy the crank if you run a geardrive. I've run a geardrive on the street for about 15 years without problem. There are others with larger cams than .560 lifts running a lock up converter also.

The duration on the intake and exhuast and the "best" lobe spread all other factors constant,,,, depends heavily on your exhaust system. The large engines seem to like the tighter spreads (106 - 108),, but you wouldn't want to run that tight with a restricted / limited exhaust - it'll causes SERIOUS torque spikes and dips.

I'd want to know more detail of what you'll be running before I say what spread is best for you - the tighter you can get the lobes (without torque spikes) the better.

 

Youre right....WS6...Im thinking of going with a 383 though still since thats what I have for now..But hey, If it breaks thats a good reason to build a 400.. Hodge, 76cc isnt too big with flat-tops, it should be around 9.5:1 to 10:1 depending. The way the heads flow(246cc between .400-.500lift) I wont need a huge cam. Im gonna go with a carb though(650 Holley) with the venturies tuned and metered right, etc. and probably a Edelbrock dual plane intake......IT should be a monster in HP and Torque.

 

The advantages of a 383 vrs a 400 IMO are the fact that there are no factory roller or 1 peice rear main seal 400 blocks.

Now if Money is no Object, then go ahead and spend the money to covert that 400 block to Roller. But if like most of us, you are on a budget, I think that the improved cam profiles the roller block will allow you to run will do more for you than the 17 Cubic Inches.

Also, 400's can have some problems with hotspots between the cylinders because they are siamesed. Sometimes this causes Overheating problems in high HP situations.


Also, the 400 block is itself hard to find, and likely to be expensive.

Eventually, its just going to be the age old question,

"How fast can you afford to go"

haha

 

400's have overheating problems due to the heads not being tapped for steam holes.

 

you can drill any sbc head for steam holes, thats not a problem. the siamesed cylinders are another issue though. but its possible to run a 400 or 406 with no problems at all. on the heads, you can get AFR to custom make you a set of SBC heads with the LT1 intake bolt pattern so you dont have to modify the intake as much, just get the distrib and cooling issues worked out and bolt the manifold on without drilling new intake bolt holes.

 

EASY 383"

....now I wonder why I didnt go bigger.....

 

400's are a great block I believe. Some people say theirs tend to overheat a lot. I had a 400 in an older pickup it was two bolt which was better for higher RPMS. But I revved it hard and had some valvetrain work done on it and it never got over 210 which is about an ideal operating temperature. I think they are a great motor for the fact of more displacement with a Small Block which means less cam to run the same HP at a lower RPM. Stay away from the four bolts because they are weak around the main journals and caps and are very prone to cracking due to the stress placed on the crank.