Is there a preferred block to use if I put a 383 LT1 motor together for my 94?
I really like my current powerband with the mild cam (213/219 465 lift) and ported heads that idles perfect, makes good low end and still gets to 320 at the back wheels in my automatic.As usual I would just like more of it. Does it seem to make sense that if I increased my cubic inches to 383 and my rocker arm ratio to 1.6 while leaving all the other mechanical components the same that I would accomplish that goal? Hopefully somewhere around the 350 mark with a slightly larger increase in the low end vs the high?
Thanks
Roy

 

There are much cheaper ways to get to 350 HP than going with a stroker motor.

A stroker will generate more torque but if you have stock cylinder heads you will shift your powerband downward because the engine will run out of air sooner. I would suggest a really good set of cylinder heads and a free flowing exhaust if you don't have them already.

A stroker motor is really nice but you'll never realize it's full potential as long as you have a stock set of heads and restrictive exhaust.

 

Nathan, I have a ton of porting time and bigger intakes in my heads, I am really not worried about them running out of breath in the RPM range I want to keep it in. I know I could get more hp, but it is the hp/torque combo that I am really after. Currently have shorty headers and stock exhaust. I may go to long tubes if I do this because I know they would really help the low end. I dont see much point in changing the factory cat back.
You may remember what I wanted to accomplish in my build is Idles like stock, looks like stock, drives like stock, pulls like a bear. I did it and it worked but now I want a bigger bear.
I dont think it would cost me that much to build the stroker. My whole top end and cam is new along with timing chain, opti and water pump. I do all my work myself. All I see as expenses is the rotating assembly, machine shop work on the block, new gaskets, and a tune. Probably a set of bigger injectors too. Then just put everything else back together.
Roy

 

Hey if you've done your research, go for it. I would seriously recommend long tubes though. There's probably 20 more HP in what you've already got with just the headers.

 

Let me try to reword my question as I dont think I really got across what I was trying to find out. I am not always so good at internet typing.
I like my current powerband. It peaks out at about 6000 RPM.
I know if I just went to a 383 (a 9% increase in size) and changed nothing else that I would shift the powerband downward from where it is now.
My question is If I also increased the rocker arm ratio from 1.5 to 1.6 (a 7% increase in lift) would this be enough to compensate for the increase in size so that my powerband stayed about where it is or is it still going to move it downward a few hundred RPM? Is it going to take more camshaft to keep it there?
Lets try that one.
Roy

 

Roy, I understand what you are asking. Stroking your motor, with only minor changes elsewhere, will achieve, for the most part, what you are looking for. However, for the trouble of going to a 383, you should be shooting for a liitle more HP, so as not to put alot of TQ into a narrow RPM range. I think you are shortchanging yourself with that very mild cam. You could UP your cam and springs (and add 1.6s if needed) and still have decent TQ, good street manners, and still afford headers and a decent tune. If you have to go a little past 6,000 RPM to utilize the improved breathing, than this is just what a healthy 350 likes. I would try this first, then if you think you need more cubes/TQ, a 383 would 'tame' the larger cam and 'fill in' some of the low end. Your current cam would be needlessly leaving some power 'on the table' in a larger engine, regardless of header type.
If we know your head flow numbers, compression ratio, tranny and rearend gears, I'm sure we could come up with some good cam specs and worthwhile mods for your 350 that would transfer onto a 383 in the future (again, only if needed).

 

Have you considered the 1.7 rockers instead of the 1.6?

 

500 hp,
I dont have any flow #s as I did them myself. I have always ported my own heads and have done more then a few sets for myself and friends before. Although not a professional I have a pretty good idea of what I am doing when I am in those bowls with the grinder. I can tell you that with the mild cam and my home port job I picked up about 50 RWHP.
Compression worked out at 11.2 to 1 but that could be adjusted with a 383 build based on piston choice. 3:54 rear gears. Auto tranny.
I have no aversion to spending the money to buy another cam, Its just that I want it to have either none, or virtually no lope at all to it. I think what I am chasing is perfect street manners, stock appearance, and boatloads of tuned port style torque while still having that LT1 top end rush that my tuned port camaro lacks. this is why the larger cubes are a draw. The cam I have now is a lingenfelter that has 0 overlap and it idles smoother than stock did. Do you have a reccomendation for a cam that will appear as stock in a 383 and still be an improvement?
93 Ragtop, I could look at 1.7s I guess. Are they a reliable choice? I already have a set of 1.6 sitting around so that is certainly a cheaper/easier option for me.
Roy

 

Roy, I have also done some porting on SBC heads, iron and aluminum. There are several areas that can be improved on, by us amatuers, and it would be foolish for oneself to NOT hit these areas while the heads are off and apart. You probably have gotten your heads to flow like a stock LT4 head, maybe even better on the exhaust side. I am sure you have heard all the buzz about the LT4 Hotcam, and it is tough to beat for a mild street motor with plenty of vacuum. ANYBODY with a hydraulic roller and 'better than stock heads' should NOT have less than a .500" lift cam, whether it's a high winding 327 or a torque monster 406. You are not taking advantage of your 'easier' camshaft ramping and the flow potential of the 'newer' better flowing heads with their faster burning combustion chambers. The Hotcam will have a tiny amount of lope at 750 RPM, but your automatic may tame that even more, depending on your desired idle speed. It has 218/228 duration at .050", and .525" lift DESIGNED for 1.6 rockers, and 112 degree LSA. This tighter LSA may be the one factor that sets it apart from your milder cam's 'smoothness', though not enough to displease anyone who likes power. Edelbrock makes a similar cam--218/218 at .050", .525"/.525" lift WITH 1.5 rockers, and I think it has a wider LSA, 114 maybe, but I am not sure. This cam was designed to go with their 170cc LT1 head, which does not even flow as good as the LT4 head. I would also consider a custom ground cam or one from TPIS that you could taylor for mild street use, but still have more lift for a noticable improvement over your current cam. The Hotcam, with its 112 LSA, would be close to perfect for a bigger 383 that would probably idle like stock 350. The issue we have to be aware of is your LSA. If you stay with the 350, you may want the wider 114, but if you are definitely going to a 383 soon, then you could improve power with a 112 LSA, then idle quality and some low end torque would return with the increased stroke/cubes.
Holy CRAP! This post got quite lengthy, didn't it?
I really believe your cam belongs in a stock Tuned Port motor.