Alright my build has hit a fork.... i can't decide wether i should build a 383 or a 355. I wanted to build a 383 but im not sure if my heads and cam selection will limit power on it. I have the Holley systemax II kit sitting in my living room with the box of harland sharp roller rockers on top of it.

my question is: will these heads/cam be a limiting factor on the extra displacement of the 383 or will they be fine.

if you need i can look up my cam card and head sizes

 

They won't limit power. If you have the exact same setup in two differently size motors. One larger like a 383 and smaller motor like a 350. The motor will make pretty much the exact same horsepower. But the torque will be larger, by about the same factor as size ratio of the two engines. So build a 383 and reap the benefits of a mild large displacement motor.

What is the combuston chamber volume of the cylinder heads you are using?

 

i really wish i could remember for sure but i think that they are 66cc combustion chambers. sumthing like180 or 190 runners but its hard to find documentation on them... if you could help me in my search thatd be great or even if i could pick up the knowledge of how to measure myself these specs

 

If you need to buy a new rotating assembly, build a 383. If you already have a good 350 rotating assembly, then build a 350.

 

ok awsome... i have a 305 rotating assembly but its stock 1975 and has been sitting. im going to send my block out for machining and just buy a 383 rotating assembly, i want to make more power than necessary. thanks very much for the help

 

383 are a waste of time and money.So either go with a 350 or go to a 400 block.

 

how do you figure.. i have a 350 block and there is no replacement for displacement. im sure u would prolly be more attuned to me stealing the 403 rocket motor outa my brothers monte and trying to wedge that in here. i just think that a 383 will be pretty nice

 

Your 305 assembly won't be balanced correctly for 350/383...crank for sure, not sure about the rods.


Always (normally) easier to build the350 than a stroker, many clearance factors can come into play.

 

BTW, what's your Bro doing with an Olds motor in a Monte?

 

Compare the cost of 383 parts with 350 parts and you might change your mind and decide 350s are a waste of money.

 

with 350`s u dont have to make clearance for the stroke which cost time and/or money.If u want more cubes in a sbc go to 400 block, skip the 383 with it`s 4.06" bore.

 

we got the car for free from my dads girlfriend. my bro is 15 lol. we need to make brake lines for the monte. now that motor was swapped into the monte by the gf's father, its weird old and actually powerful. i was gunna swap it into my car but the wedge of the heads is so serious that i think itd be too much work.

i dont know what thats supposed to mean but i have a 350 sitting in my shed... and i was planning on buying all the new lower end. there are deals to be had for 383 kits in chevy hiperformance. clearancing isnt a problem and neither is time. ive been working to build this motor for about a year now so i think i can wait longer.

 

if your 305 crank and rods are good you can use them for the 350, same exact parts, just get new pistons, or build a 383 stroker. Up to you.

 

Sorry about that, I mistook your post above about "having a 305 rotating assy" as that was waht you were going to use for a 350 build...I need to read more, drink less

 

Most blocks don't need so much clearancing that it's really a concern. Consider it part of the deburring and polishing that should be done anyway. Sure a 400 block is a better idea if you can find one, but they're getting less common and more expensive. 350 blocks on the other hand are more common than dirt and about as cheap.

 

if anything the 350 i have still has the stock rotating assbly i just would rather make a 383

 

The rods are the same, but the cranks are different, despite having the same stroke.

 

different journal sizes

 

No, pretty sure journal sizes are the same on them, but balancing is different

 

the 305 has smaller journal size compared to the 350 i beleive. either that or there was a small journal and large journal 305

 

Both have the same journals. The 350 crank has larger counterweights to balance the larger pistons. You could use a 305 crank to build a 350, but it would end up being expensive to balance.

 

oh ok

 

Takes about 10 minutes a rod. For real. That means a little over a hour. All you are clearancing for is the rod bolts. You could even use some of the 383 HT rods that don't require clearancing. I would build a 383 over a 350 or a 334 over a 305 anyday.

 

I'm buillding one. my stock 350 crank needs to be turned, and that's $135. I bought a stroker crank, including FREE shipping on ebay for $185. stupid? i dunno. seemed dumb to me to build a 350 with a smaller-journal crank. my pistons are screwed. the have small flecks and pieces missing and generally look terrible. needed new ones. the ones i want are $230, including shipping. KB hypers. new stockers? $150 for a set, AFTER my 20% employee discount at autozone. my rods? they're stock. might as well put some nice lighweight forged I-beams with bushed ends. (my pistons have locks for floating pins). those are another $180. including shipping. i bought an SFI balancer and SFI flywheel, and I got them for $200 bucks as a set, including shipping. my bearings and rings and gaskets i got from the zone, and they cost me $120. since i needed everything but the rods, i only spent about$260 MORE than the cost to build a 350.

If i wanted to sound like a knuckle-dragging *******, I'd get into a pissing contest about a 350 vs a 400. I'll just sum it up like this:



I think it IS stupid to build a 350 for $260 buck less than a 383, and a serious waste of money.

 

What he said^^^^. No replacement for displacement.

And for those that are saying build a 406. Try finding a block in my area. I have been to 50 yards in the past year and have yet to find 1 400 block much less a good one. No luck in the local classifieds either.

 

fast,you can find them in swap meets here in ohio,but that's a ton of shipping $!
as for the clearance issue,scat's capscrew rods pretty much reduce the tools needed to a half moon file if that's all you have.they have 7/16"bolts and are a balanced set.also they are super strong.about $230 if you shop ebay or check dirttrackthunder.com ,good dudes to deal with!you can get an internal or external balanced 383 crank cheap as well.oh yeah,i chose the 6"rods and have never heard of a problem with them on a correctly assembled engine.for pistons i am going with the wiseco 20cc dished,to match my 64cc heads,along with a .015 steel shim head gasket for a final static compression ratio of right about 9.5:1 and a dcr of 7.755 with a .040 quench!this thing should make good power on 87 octane and might run on kerosene!
just a thought,
Eric B

 

Don't fool yourselves by thinking that getting a 400 will solve your having to "clearance the block issues". That is, unless you plan on keeping the stock bottom end and crank/rods.

But then you have to deal with the external balnce issue - which is a bigger problem if you run a T-5...not so much with an automatic (they sell offset weights for flexplates).

But then again, clearancing the block really isn't a big deal.....I'd opt for the 383 in a heartbeat over a 350 if I had the block already - why?. As said above, much more torque!

So what if the heads/cam you have are a limiting factor with the extra displacement....you don't have to pull the entire engine out of the car if you want to upgrade with better cam/heads later on to take advantage of the extra cubes.

But you'll have to pull everything out again to change a 355 into a 383....

JMO...

 

thanks for all the advice.... now i have to explain to my father that a 383 is a better choice.. sigh. its my money anyways so all he can do is complain