Im currently knee deep in my engine rebuild. And I've already purchased my new cam, springs, rockers, valvetrain etc. Now Im going for the internals. Now Im staying with the stock 350 block but Im not sure if I wanna go with a 383 or keep the 350. I've heard that if you use a 400 crank with a 400 harmonic balancer in a 350 block that it would make a 383. Now Im sure Im missing other things to this equation could someone help fill me in. Also I was looking online and there are some cranks that say 383,400,377. Im confused. Do I use the 383 or the 400. And whats the deal with the 377?? I know these numbers are just measurements on the crank but I dont know where to begin..??

 

Well back in the day you would swap in a 400 crank and the dampner flywheel ect... However all you need is a crank, and a 30 overbore to make a 383. Without the 30 overbore you get the 377. Eagle, Scat both make great replacement cranks that will increase the stoke to make a 383. www.cnc-motorsports.com sells them at a good price. You can get a cast or forged crank to meet the needs of your engine and the depth of your wallet. Hopefully if you are going to go with the 383 the cam you purchased will be large enough for the motor. Alot of people under cam their 383s, and make sure you get some decent heads, don't throw the stock ones back on. Hope this helps.

 

Along with a new crank, you'll need to change the pistons or the rods to build a 383.

The old fashioned way was to use the 400 crank after grinding down the mains to fit the 350 block, along with 5.565" 400 rods and 350 pistons. Nobody really does it that way anymore.

The preferred way to do it these days is to buy a 383 crank off the shelf and use it with normal 5.7" rods and a set of 383 pistons.

If you have to replace any of the rotating assembly parts, then the 383 doesn't cost much more than a 350 to build.

 

Hmm, So is the 383 crank really just a 400 crank but modified to fit the 350 block ?? I'll prob just get a 350 crank, and just have my cylinders bored .030 over. I've heard that doing that makes it a 355 is there any truth to that. But other than that I'll prob just keep the standard sized crank until I atleast graduate and have more time and $$money.

 

if you have to buy a new crank, and new pistons, then use 383 parts. a 383 crank is within 5-10% of the same price as the 350 crank (usually same price) and pistons may be 10% more. You'll get much more power though.

I'm kicking myself, I paid $180 to machine my old 350 crank, when I could have gotten a 383 one for $200.


yes, a .030" bored out 350 is a 355, not gaining much HP from those 5 cubes though, it's the 33 cubes going to a 383 that makes the difference

 

What about the rods do I have to get new rods ?? Mine are the stock 5.7"
Im prob just having them cleaned up and checked and use them if theyre good. But Im already buying a new crank and pistons so I might as well just get 383 parts. But again would I also have to get new rods ??

 

no, you can reuse your stock rods.

however, stock chevy rods are the main weak point in a high performance motor, specifically, it's the rod bolts. you can put in ARP rod bolts, but then you usually have to get the rods resized.

my machinist told me $90 for the ARP rod bolts, and $150 to resize them, = $240. I got new ohio forged rods, with arp bolts, 6 point nuts, for $250. (canadian dollars, to my door). You can get those rods for $159+ shipping. I'd recommend that.

 

Woa, thats a good price. I've looked at rods and I've seen them in the 300's thats why I figured Id keep them if they were still good. Oh ya do you think the 383 will work ok with a XE256H cam ??

 

bump

 

It will work fine if you have low compression. That cam is really small more suited for a 305, but it will work to about 4500 rpm.

 

yea, better rods are in the $300's. Summit/Jegs/Eagle entry level ones are ~$250, so the ohio ones are a real steal.

I agree with Leigh, that's a very small cam, 'specially for a large displacement motor like the 383.


oh yea, a 377 is a 400 block with a 350 crank, just like a 383 is a 350 block with a 400 crank. Why anyone would want to do up a 377 is a mystery to me.

 

Well the cam has good lift though .449 / .456 Its alot better than my stock one. It will do for awhile I guess. It said that it will work up to 5,200rpm. I got it because I didnt want to have to change my converter right away. So basically it will work with the 383 but just not optimal.

 

That cam is to small for a 383. Trust me when I first built my 383 I used a cam close to that so I could get a clean idle. It was a torque monster. But I dont think there is any easy way you could hook that kind of power up. Now I have a 224/230 .510/.520 and it still shreds em and has a killer top end. Well for still being a TPI anyway.

 

I did really need the new converter though. I got one now

 

That sounds ok to me. I love torque, I dont really do much top end racing. I mostly just cruise to gatherings and do stoplight racing. And the TPI and torque are optimal for that use (IMO). Of course this is nowhere near what I tend to have for the long haul, Im only 17 and work all the time and still dont make that much. Once I graduate and Im pulling some more cash I'll get another cam. As far as hooking up I have plans for that,

 

I love torque to but I Couldnt get it to hook up that well and I was tired of only pulling high 13s. I got beat by a lightning and my buddys 89 mustang 5.0. So I got mad and just bought a new cam. Now I just want a HSR to get this 383 in the 12s

 

Ya, sounds awesome. I plan on doing a intake change eventually, HSR or maybe Miniram undecided, too soon anyhow. But I rarely go to the track I've only gone twice (dont have time). I agree it is too small to be good in top end, but right now I think I'll just get the the internals together and save up some cash and when I get my bigger cam I'll get my new intake. As for now I'll be content with a street going torque monster. Plus burnouts are always fun for the whole family LoL Thanks for everyones help. Oh yea thanx evil for the link to cnc-motorsports, I checked them out. Theyve got some awesome deals on the best stuff. Internal engine parts; crank,rods,pistons etc. until recently I didnt know awhole lot about. Really appreciate the help guys

 

No prob. Have fun with the cam. It is def fun to play with on the streets.

 

Im buying roller rockers to finish up the valvetrain so what type should I use the 1.5 or 1.52. Im not getting the 1.6 because that requires modification to the pushrod hole. Also what type of pistons should I get: domed, flat, because Im using the 383 Im getting 383 pistons but what type. Im getting speed pro's but they have alot of different types.

 

what heads are you using, what cr do you want?

probably flat, domes are for with huge chamber heads or if you want giant compression needing race fuel, and...racing!

1.52 and 1.5 are essentially the same, pick a good brand and good value. Avoid stamped steel types. Comps are a good value.

 

Im using the stock L98 heads....but wait before you guys jump on those pigs, Im porting them a good bit. And Im gonna use new valves. Id like atleast 10.1:1 but I'll be ok if its not, but Im just not getting new heads right now tooo expen$ive!!! If I remember right I think I've heard of them referred as the 416's not sure tho. What cc are they I think theyre 64cc or 68cc ??

But ya as far as the rockers Im gonna go with comp. I've used them before and my dad, friends, family, always use comp, they swear by them. So if theyre both the same 1.5 or 1.52 whats the diff I've seen them the same price should I just go 1.52 ?

 

bump ^^^^^

 

Rockers are just a lever. When 1 side moves up 1 unit the other side moves 1.5 units.
Well the cam you are going to put in there is only .447 / .454 lift at 1.5 ratio. So if you divide that by 1.5 then multipy it by 1.52 you get .452 / .460. It might be worth a hp or 2.

 

Very cool man. Not to split hairs but my cam is actually .449/.456. But that doenst make much of a difference.

 

You get the idea though. My memory must be giving out on me.

 

Yea man, I get the idea. If I eventually wanted to go to the 1.6 ratio what modification to the head would I have to do?

 

Ive never had to do any machining but im not working with roller stuff. The only thing ive had to do was replace the pushrods with a differnt size to keep the roller on the center of the valve stem. I was replacing the heads and gaskets so that may have been the reason I had to change the length.

 

I heard somewhere that if you use 1.6 rockers that you had to port the area where the pushrod runs through. But maybe thats only if you dont change pushrods.

 

You might have to clearance the heads, or you might not.

 

Thanks, I think Im just gonna use the 1.52's. Im not gonna worry about using 1.6's for right now. You know the funny thing about all this is that before I got into my perf rebuild, it was just supposed to be a rod and journal bearing change. And then before you know it your on summit saying "you know since Im already in there why not a 383 crank and then your saying well then I should get new pistons, then your saying I need rods to back it up, then your before you know it your ordering a 150 Nitrous express kit" But if theres one thing I have to be addicted to Im glad its my camaro and the never ending search for more horsepower.

 

If you are going high compression remember that it is a bad idea to use power adders! You will blow head gaskets.

 

i say do the main mods like the crankshaft now while you have it open

 

I have a question concerning balancing my rotating assembly once it all arrives, pistsons, rods, crank: they were all bought with external balance. What kind of changes will be made to put it on the car , flexplate dampner. Do I need to have it then internally balanced. Can a shop do this for me. Or can I just buy a new flexplate and dampner and leave it. ??


Nahh Im not going too high of compression rockstar, somewhere in low 10's. Around 10.1:1. Nothing to high, I dont plan on using it alot or even at the max 150 so I dont think it should be a problem, since if I make it too low I wont have the power I want unless Im spraying it all the time.

Bahsarie, ya I figured while Im at it why not build it the way I wanted it.

 

The whole assembly still needs to be balanced by a shop, regardless of whether it's done "internally" or "externally". "External balance" just means that some of the balancing weight is on the flexplate and balancer themselves, instead of all being inside the engine.

 

Oh ok thanks, Im gonna take it down to the machine shop where I had alot of my other work done. But today I just a bought a 96' corvette LT1 with T56 six speed, with only 37K, I had to get it cause it was only 1,500. I head the motor run and its in excellent condition. What should I do, continue to build the 383 and just sell it and use the LT1 ??

 

Whatever turns your crank.

 

i'm confused.. you bought the whole car for 1500? why would you tear apart a vette to put the engine in a f-body? maybe I'm reading this wrong.

 

Nah, 89'. I bought just the motor, the guy who owned the car was friends with the owner of the machine shop I get work done at. Its having an LS1 swap, and they took out the LT1 complete with T56 and sold it to me for a great price. Also the LT1 has some port work done on the heads, has the MSD optispark, headers, and some LT4 parts, I believe it has the LT4 valves, and injectors. I just dont know what will be best for the long run; as far as gas mileage, reliability, compatibility, and just general maintenance. My knowledge of LT1's are limited. But I know that they are a better setup than TPI's. So can anybody can tell me their honest opinion. Im leaning towards the LT1 cause its got a six speed. So anyone got an opinion on this let me know 383 TPI or 350 LT1 w/T56 ???

 

^^^^^^Bump

 

the lt1 with the t56 would be cool but that is a hell of a conversion. You would have to get a cluch pedal and bracket, a new transmission mount that is like 3" farther back. You would would also need to find a new center console for the stick. The speedo should hook right up in a 92 i think. I dont know about all the other gauges. That was a really good deal though. A T-56 and an lt1 with only 37,000 for only $1,500 is sweet. If you feel your up to the work the lt1 & t56 would be nice. I would get a bigger cam for the lt1 while i had it out of the car. You dont have to worry about the converter anymore. I put an lt1 cam in bandit45's 305 camaro and it still seems small in that. With the lt1 intake, head porting and headers, id say that cam is the weak link