I’m in the market for a forged rotating assembly (355), where is the best place to get one? I was leaning toured Scat to keep it somewhat reasonably priced

 

Depends on your power level, but the general consensus is that if you're using a 355 at just about any reasonable HP level then the stock one is the way to go. You could also get away with reusing stock rods if all you're doing is a LE2 H/C. Add on top of that a good forged piston and you're good to go.

 

My crankshaft is toast, spun 2 mains and the bearings ate deep grooves in it. The rods are not salvageable either, spun 4 of them.

 

Well crap then!

If you're on a budget I'd try and find a cheap used OEM crank or an OEM shortblock.

 

The thing ran to, I drove it home from the track like this. Im going to rebuild it or get a new shortblock

 

IMO, if you're going to invest in something other than a stock stroke crank, you might as well go 383. It's only marginally more expensive (block clearancing).

 

Where were you getting prices? AI sells the Compstar 355 or 383 kit for $21xx, the scat kit I was looking @ was like $18xx-$19xx. Would it be worth the little more $$ for Compstar?

 

+1 for Callies Compstar. Quality stuff. Just remember, you get what you pay for...

 

It depends on your budget and your goals. I don't give a rats *** who says their kits are balanced and ready to install, if you buy and assembly you better have the shop balance it.
That's all I am going to say for now lol too many variables to give adequate advice at the moment.
Not everyone wants a full bore race engine, nor do they need one. Until you give a few more details it would be an educated guess.

 

This car will be my DD that’s why I was going for the 355 instead of the 383. The goal for the car is to have 400wrhp and be a fun reliable car. I already bought the complete top end, we were trying to do this for 5k-6k but now that it needs a rotating assembly it’s looking more in the 6k-8k range.

 

If this is mainly your DD then you want the most torque you can get, this is what gets the car in motion, HP is good for the upper end of the RPM band sort of say. If you are mainly going to play light to light, go for the torque, go 383. As said I'm also not going into the debate of 355 vs 383, You can build more torque with better street manners with more cubes..

 

i see wat u did thurrr.

 

I have made my mind up and I’m going with a 355 due to the budget being so strained. In looking I found this http://www.cnc-motorsports.com/produ...389&CtgID=9015 will it work and is it a good deal??

 

I use them for my parts and I have never had ANY complaints I would, if it were mine, use a longer rod. I would go at least 6.0 (in fact I did ) Talk to Jpack I am sure he still has the literature somewhere and we both did a long rod 355, he used a 6.125 and I went 6.0. He was well over that hp mark as am I.

 

like gator said. do 6.0 rods

 

Stock crank and rods here. Bought a reman crank from autozone for $150 or so, installed ARP main studs, ARP bolts in the rods. Had the rods and the block resized for the new hardware. Then fitted SRP forged 11.7:1 pistons that were .030 oversized. Got a deal on an older set of LE3s and CC306 cam. Then 1.6 Comp Pro mags, Melling 10% over oil pump and Moroso 7 quart pan. Been spinning the combo to 7k rpms for 3 years now. The package works great together. Mean idle, enough torque to pull the hills around here in 6th gear at 1800 rpms, and tons of topend power. But after 3 years I'm ready for more. But thats another story.

Also should add that I have full bolt-ons as well. EGR block off, LTs, 2.5" true duals, CSR EWP, CAI, and more

 

I'm also interested in a budget rotating assembly; like the above setup since I just blew up my cam only stock lt1....What exactly are the weakest points in the bottom end? The stock rod bolts and connecting rods themselves? Pistons? I know the stock crankshaft is pretty stout. I just want to get 400 RWHP and spin to 6500 RPM with no worries.

 

The oil system is the weakest part IMO. Then the rods, in hind site I should have upgraded to some h beam rods, but everything has been good to so far.

But in all honesty I regret not going 383, but I'm extremely happy with the power my car makes. And I average about 17 mpg with town driving and **** pounding the car haha, thats what I built it for, not to get good mileage


But before I built my motor I did alot of research and for my budget this was my best option. IIRC people have said that the stock crank it good for ~600 hp and the rods are ~450, but I think the main studs and good rod bolts help out alot. My rev limiter is set at 7000 rpms and I have hit it plenty of times. I try to shift ~6700, but my tach is slow. Sometimes I hit the limiter when the tach shows 5500 rpms.

 

It is very very complicated to explain. I know you know some of it already, and I know if I laxadaisically explain it there arew enough folks that know all of it that will chime in and burn me for being short lol. I will explain it in extremely short summazation. The name of the article you want to search for is called Long rod shortblock, the motor GM should have built. Jpack has the article, but it has been in the know for years, just kinda kept quiet and until recently the technology made it not so great for the street.

The dwell time that the pistons sits both TC and BC makes a big difference in the amount of fuel burned, air swept and volume obtained. The efiiciency is much enhnanced. Couple that with the reduction in friction from sidewall loading due to the corrected angle of the piston from the longer rod and your motor gets really happy. Where folks get all bent out of shape is that the stock stroke coupled with the longer rod doesn't really make a stroker motor, but it does ease the burden on the rotating assembly no matter how incremental. So as for the 355 vs 383 thing, there is no replacement for displacement, but to rule out a 355 is ridiculous. The faster car makes more explosions at the big end of the track, which equates to RPM, and RPM translates to HP. By law of physics the tighter, smaller circle will be able to spin faster than the bigger circle. They may both be able to achieve the same velocity (RPM) at some point in time but the smaller one will get to that point faster because it has less to go..........<-----that will be an argument, however thats not what this is about lol

One of the main reasons this was seen mostly in track cars and the race scene wqas due to piston technology. The wrist pin ended up well into the ring lands, which is something you wouldnt want in a daily driver. Today piston manufacturers are able to push that envelope all the way across the table. I will see if I can find that article and post it up.

http://purplesagetradingpost.com/sum...%20engine.html

 

^^^2 very well put posts


On a different note I was browsing my speedway motors catalog and you can pick up a forged scat crank, forged icon pistons, and forged scat rods for $1300. Not a bad deal IMO