This is my first engine build. I feel stuck doe's any one have any real world PRO'S CON'S to ether or. THANKS

 

383 =

 

A PROPERLY done 355 will be more than is really usable at legal speeds on the street. Problem is most people don't build motors right, bench racing gets in the way of what actually works. So they end up with 383s that just don't work well.

Displacement is less important than the topend too.

 

Johnny, there's nothing wrong with building a great 383, but a 355 will be cheaper and you can use the stock crank and rods which are good pieces, and choose some good forged pistons. Have the rod bolts replaced with stronger ones and the rods resized. If you really want to spin it a lot, you may want the 4 bolt main conversion, but otherwise stud the 2 bolt mains and put your money into some worked heads and a matched cam by someone who knows what they are doing, and be sure you are being realistic about how you want the engine to be used. IOW, don't choose a giant cam that needs to run above 3500 if you are going to DD your car. Make sure you build your lubrication system correctly. Don't skimp on the little stuff - buy good fasteners, bearings, and gaskets and make sure you have a good machinist to bore & deck your block and align hone it, then balance the rotating assembly. Good machine work will cost you a bit. Spend some time setting up your valve train correctly - and get help if you don't know how to do it because the forum is full of valve train screw-ups. If you do all this, you will have a great street/strip engine and will be happy with it.

 

Yup

 

x1000

 

being you have a 2500 stall already. unless your planning a bigger stall..

think i would go with a hotcam kit 355 build... deck the block .015 or .020... get summits speedpro forged piston rebuild kit.
and follow the guidelines of kevin blown 95 ta...

think i would just have the stock heads rebuilt with 1.94 1.5 undercut stainless valves and the lt4 springs locks retainers and cups....

think it would make a good solid streetable hotrod engine..

 

Why would you replace the stock valves without doing real head work??? The LT4 springs are about right for a stock cam with 1.6s but not much else.

I would continue with a stock shortblock before using the Summit kit.

There is MORE marginal to bad information available on the forums than good so learn to sort through it before following any of it.

 

lets see, a rebuilt set of stock heads using 1.94/1.5 undercut valves using the lt4 hotcam kit components would run about $250-$300

a set of ported heads done by someone that knows what their doing is going to run $1000 or more....

so it depends on if the op wants to spend $2000 or $5000

hmm lets see, how much does the op want to spend?

the more i see these posts about people mixing and matching components, the more i see their builds go to ****..

the hotcam kit seems to have a pretty good track record as being a solid kit..

hes got a 2500rpm converter so the hotcam is about as much cam as hes going to be able to use.. lunati has some good looking cams and components also.. lunati 60121 would work good with a 2500 converter.


yep so to the op, pick and choose who you listen to...

stick some ported heads on their with a big cam, and a 2500converter and have an overpriced pig of an engine that wont have enough torque at 2500 rpm to get out of its own way.

 

Thing is STOCK cams even the stock b-body cam likes stalls over 3000rpms.

The money you are suggesting he waste on new valves would be MUCH better spent elsewhere and the LT4 springs are NOT really good enough for the HOT cam without special lightweight valves. The LT4 got hollow intake and sodium filled exhaust valves, to get aftermarket valves that light to be able to use the LT4 springs would be really expensive.

I am not suggesting he spend the money on full professional porting. I am suggesting he not BLINDLY replace parts simply because they are stock.

Besides building a 383 like he asked about, and not putting a couple grand into the heads and valvetrain would be a really poor idea, 100% of the air moves through the topend so it is better to put your money there and not worry about adding displacement if you don't have the coin to do BOTH.

 

the thing is he has a 2500 stall...and for that stall a hotcam kit would be hard to beat...
the undercut valves reduce the weight of the valve so they dont float plus they improve flow, so for a $100 set of stainless undercut valves its a budget performance upgrade..

i would use either a hotcam kit or a lunati 60121 with 1.6 rocker arms.. i think the lunati would be better but it would also cost a couple hundred more..

the stall is a limiting factor i'm also using his 2500rpm stall to choose the cams, go to a higher rpm stall and i would choose different cams..

its pretty simple..

 

Do you have any documented proof that aftermarket undercut valves increase performance on these specific heads??? Or are we just blindly bench racing?

 

weigh an undercut valve, and weigh a valve thats not undercut.. its pretty simple.. weigh a corvette valve and weigh an undercut valve, tell me what you find. weigh a titanium valve while your at it...

and yes i have weighed an undercut valve compared to a valve thats not undercut and the undercut valve was lighter.

take your ai heads off and see what valves are in them, take the valves out of a lloyd elliot head and tell me what they are.. hell take any aftermarket head on the market and see what valves are in them... the only heads that you might not find undercut valves in are heads that had guides put in them and their using smaller stems compared to stock, such as a big block head using small stem valves..

if you look around i'm sure you could find flow numbers on 1.94/1.5 or 2.02/1.6 in stock heads... when you please tell me what you find..

 

So you are blindly applying information not specifically found on LT1 stuff?

I know what is in my heads, and I know there are better ways to spend money than to take baby steps upgrading the heads. I tried doing things in baby steps and it is a waste of money.

Far as head work I would say springs and rockers are fine on otherwise bone stock heads but would not go beyond that unless REALLY doing it.

Sure you could spend some money on lite valves and valvejob and endup with $400 in them EASY and you just made them less suitable for real porting later on as a decked head complicates things on a CNC and you could end up sinking the valves a long ways with repeated valvejobs. So I fail to see a good reason to do this halfway.