What all is needed to go to 355 ci and is it worth doing? I figure if i ever rebuild my engine i will do it. How much hp is typical and what else is nice. What do you need and how much on average does the conversion cost?

 

You bore it 30 over. So you have to completly rebuild it (which I know you plan on doing someday anyway) have to have new pistons of course. It only cost a few hundred $$ more to go 383, that's what I would do.

 

I thought it only costed a few more hundred to go 383 also. I think I was wrong. Summit sells an affordable forged kit for about $550. Reuse your crank(after reconditioning, ie polishing, turning the crank). My problem was I got carried away and didn't want to buy the stuff a little at a time so I just sold all my old headers and stuff and bought all the parts to support the 383. Thats where it got expensive. I just wasn't content with doing little by little so yes, it is a few hundred more and it isn't depending on how you look at it. I don't think on a stock rebuild( stock heads and cam) that you will see huge gains. Head and cams will net you the bigger increases but then to see full potential you'll need all supporting parts.
Machine work to the block including adding 4 bolt caps was almost $900.
Valve train ( LE2 heads, cam, rockers, pushrods, gaskets) $2000
Rotating assembly& balancing $1200
58MM TB, Hooker LT, Y-pipe $1000
New sensors & misc items (GM) $300
New opti & Waterpump $400
Torque converter & tranny cooler & shift kit $800
New 37 # injectors, Lloyd Elliot ported intake, Racetronix fuel system upgrade w/ upgraded wiring harness $700
New Z06 rims and tires $1100 I know it don't really count but what the hell my Debit card was getting about as worn out as Rosey O'Donnells' fork!!
There are countless other items I am missing, but I have kept every receipt so when it is all said and done and all bugs are worked out I will do a final tally. I just hope the 10 bolt lives thru summer, 12 bolt next year and most likely a tranny rebuild.
If you are not looking to make huge power or if you are able to ,go .10 on the bore. If you decide later to go bigger you may be able to go .030 or even .040. I wouldn't go .060 over as the newer blocks don't have as much meat as the early 70 blocks did. In the 80's they started casting the blocks thinner to make them lighter. I had a Monte SS I went .060 over and the block was a 72, and it still ran a bit hot.
Your budget will dictate what you can do, mine didn't really call for everything I did but I guess I don't mind eating PB&J and Top Ramen noodles for the next 2 years

 

Damn right. If you build a 383... and you want to do it right... plan on spending no less than $6k. And that's not counting an exhaust system.

And by the way... you might get about 5 horsepower by boring 30 over... so don't let that be a basis for a rebuild.

If you're dead set on building it... buy some nitrous and spray the hell out of it till it blows. then build it.

 

But most of the costs noted by "97zgreenmachine" would be identical no matter what the displacement was... You can't attribute the cost of the Y-pipe, heads, cam, 4-bolt conversion, convertor, shift kit, opti, waterpump, sensors...... blah, blah, blah to the fact that its a 383. You would put the same things into a 355 if you wanted to.

 

I was just getting at I spent more than I originally had "thought" it would cost. I realize what he had said about "a few hundred" more as thats what I thought. Why would anyone spend 6k and reuse a waterpump? I depends on the person and mileage and blah, blah but for me I figured it was worth getting new sensors, opti, water pump, etc. Also I wanted full potential(budget allowing)instead of buying parts two or three times( I have been there, done that)so for me the cost of the converter, y pipe, headers was all relative to the build.It really is more of an eye opener as to cost associated with a rebuild( my experience). I am sure it can be done cheaper and it could cost alot more. Things also tend to get a little out of control when you start. You decide I am not going to skimp here or there so the costs start to creep up on you. Thats what I faced. Looking now, I could have gotten a Golen 383 with some AFR's for what I spent. I am sure there are more options out there.... so Fred, long story short...your right, it can go both ways for any size motor rebuild. I just wanted to shed a little light on thats what I thought about a few hundred bucks, but for someone who thinks maybe a few hundred or 2k and you got a rebuild, they are wrong.It's the little things that are adding up, so beware. It probably why I did what I did cause I hate doing things twice or more like spending money twice. I suppose I could probably take off about 1K for all my old stuff I sold on Ebay.

 

What I should have said is...........I wish that's what I would have done. I spun a bearing November of 2003, spent 8 months building what I have now. That being said this is how the conversation went with the old lady........" I can rebuild it for $500.00 BUT I wanna have a little more power" So I told her I would probly spend about $2000, then I told her $2500, then $3000, then I jumped straight to $5000, it ended up being right at $7500 and I'm still not where I wanna be (never will be ) So my point is once you get a little power you'll want more so you mine as well do it right the first time. At the time I REALLY had a $2000~ budget but as you can see I went WAAAAAY over that, if I would have known I was gonna spend $7000+ I WOULD have went 383..........oh well to late now! That's just my .02.

 

According to your profile, I see that you are shooting for 450 rwhp through an A4 with LE2 heads. That is quite a feat. I have a 383 M6 with LE2 heads and a 236/242 cam and im shooting for 430. Stock ported heads dont support enough flow to make that much power in a 383. You wont make much power over 6200 rpm, so 450 rwhp seems a bit high. Not to rain on your parade, just giving you a heads up that its a little far shot.

Well... actually its hard to say. I dont know of any max effort LE headded cars. By max effort, Im talking attention to every detail. There are alot of little things that will pull more power out of a motor than simply head flow, cam design, and bolt ons. There are things like quench and compression that can increase power. If you set up the motor to .032-.035 quench (.032 is close, but possible w/ hypereutectic pistons) it will make more power and let you run a bit more compression (there is also effective quench, but that a whole new beast involving metal expansion....). Setting up the dynamic compression to the highest possible given the local octane and weather conditions will net you more power. You can also squeeze more power if you use a top ring gapless set of rings. It will seal better and pull more airflow out of the heads on the intake stroke as well as reduce blowby (this is usually pretty controversial, but im a believer). Accurate balancing and running a lighter rotating assembly can also make some more power. You could also get some more power with a lighter valvetrain. If you use beehive springs with TI retainers (and maybe a good rev kit) and some lightweight valves, then it will minimize the valve bounce when it shuts (as well as reduce valve float). Then you have custom cams and assembly.

I think I am starting to ramble, but my point was that attention to the little details is what separates a quality professionally built engine from an engine that someone just throws together. Making power is all about understanding how the motor works and utilizing it.

 

Sorry. I posted that to the wrong person (94zgreenmachine). i dont mean to threadjack, but I still think it is relavent information to any engine buildup.

 

You are still missing the point. I am in no way criticizing the fact that you put a new water pump in, or that you bought the best possible parts. I'm in 100% agreement with you, do it once and do it right (go look at my mods list if you don't believe that).

I am simply saying that your response was misleading, since it appeared to respond to 30696bird's comment about "It only cost a few hundred $$ more to go 383". He was right.... a "correctly done" 383 is not going to cost much more than a "correctly done" 355. One may cost $3,000 and the other $3,500 if you go the "Golen" route, or it may cost $10,000 vs $10,500 if you go the "gold plated" route.....

Just trying to clarify for "searchers" who come across this thread that the parts and costs listed in your thread were not determined by the displacment of your engine.

 

In my experience, any full rebuild or partial build (top end, bottom end) will cost twice as much as you think it will. Maybe not twice but it always seems to grow a considerable amount.

 

From what I've heard, the 450 rwhp mark can be hit with stock stroke and stock castings, but they must be put in the hands of someone who has really had experience building no-compromise motors (read: Trans Am series, World Challenge, etc). The castings have the potential, but you might spend $6K on porting to get there.

Once I get out of school I plan on having LG build me an AFR 210 - headed 355... it would be kinda nice to run 10's on motor ... Until then, I've gotta get back to studying for exams.

Good luck!

 

hrmm, can't you get a one-piece rear mail seal GM Performance parts 4-bolt 350 shortblock from sdpc2000.com for like ~$1800 shipped?

or is that not compatible with LT1 heads etc ?

 

not compatible

 

Ouch...well, I think your only shooting for 430 cause of your cam selection. Mighty small for a bigger motor. Same cam I've got in the 350 AND ported LT4 heads. Buddy of mine has a 383 with some AFRs, and a pretty big cam. He's making 495. Why didnt you solid rolle that thing? Driveablity issues??