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scat vs pro comp rods in a chevy 383

22K views 25 replies 13 participants last post by  327NUT 
#1 ·
Hi, i need your opinion on this one
I just got my hands over a Chevy 383 rotation kit, external balanced Eagle 5140 crank, flex plate + damper. Sealed power flat top pistons, this kit also came with Pro Comp 5,7 rods,, the documents from the seller says its balanced. but i have heard so many bad things about those pro comp rods, and that has made me not wanting to use them ,but i have a set of new scat rods but they are 10 gr. heavier. Will that take the motor out of balance or is that OK to do ? This engine will go in my brothers daily driven 76 corvette and see max rpm of 5500.
Thanks and best regards. Kristofer.
 
#3 ·
hi and thanks for your reply, when i weight those rods it seems to me that 7 of those 10 gr. are at the big end.
I sure would have the kit re balanced but here in Iceland it is not possible because no one has the equipment to do that, sucks !
I would prefer the scat rods if they wont take the engine out of balance ?
Thanks again. Kristofer.
 
#5 ·
I have never seen a Pro Comp rod and have no desire to ever look at one. Scat makes some nice rods and I will blindly say there is no comparison. Scat rods are used in so many performance applications and have been for so many years it does not make sense to save a dollar on some cheapo rods. I am not sure how long it's been since the introduction of the Pro Comp brand but it has been some time, and there is not a lot of rave about anything but the price, which is really not a savings at all. To me using this kind of stuff will result in nothing long lived or good. I have yet to see anybody at a dragstrip bragging about their Pro Comp anything! Any roundy round guys out there use em that reading this? I'd guess their engine guy would not use such an item unless made to do so. Even if the price is really cheap, how will the machining and accuracy of the rod stack up to a quality one? I suppose for a slap together don't care if it lives not too tuff of an engine, they might be okay - IF they all checked out and good. But why have to go thru all of that?
 
#7 ·
Kristopher

If you have a gram scale, you may be able to make up a setup for balancing the rods yourself, or at least to match them to the pro-comps.

Now, let me make this clear I AM NOT AN AUTOMOTIVE MACHINIST, but I feel comfortable I could do this in my garage. On the other hand, I am not certain about the best place to remove the weight (other than the balance pads) and I am not certain that the pads can shed 7 and 3 grams. But, I'd be willing to give it a try. Small gram scales can be had for less money than a set of good rods, and I think you said you had the Scat rods already.

Good Luck,

Pat
 
#8 ·
PatM said:
Kristopher

If you have a gram scale, you may be able to make up a setup for balancing the rods yourself, or at least to match them to the pro-comps.

Now, let me make this clear I AM NOT AN AUTOMOTIVE MACHINIST, but I feel comfortable I could do this in my garage. On the other hand, I am not certain about the best place to remove the weight (other than the balance pads) and I am not certain that the pads can shed 7 and 3 grams. But, I'd be willing to give it a try. Small gram scales can be had for less money than a set of good rods, and I think you said you had the Scat rods already.

Good Luck,

Pat

I agree, you could do this yourself. Take a look at this article and give it a whirl.

http://www.angelfire.com/ca4/CorvAIRCRAFT/RodBalance2.html
 
#9 ·
Pro Comp parts

Hi,
I have just recentley waisted money buying a stroker kit for my 350 through Procomp.
The kits are of poor quality and once i did some reserach, I heard some bad stories about them.
The problem I found was that one of the rods was hitiing on the Cam, most of the bolts had to have a angle on them to stop them hitting the block and also the sump.
Now for the crank, this couldn't be balanced as it would look like an old bit of chedder cheese and have stories that guys have stripped flex plate bolts too. ABSOLUTE RUBBISH.....
The quick stoker kit ended up costing about $7000 by the time I wasited all money on the ProComp rubbish and finally buying some Scat parts..

---- Note to self, don't ever buy PROCOMP parts for any of our cars again---

Jimbo :nono:
 
#11 ·
I tried saving too, but by piecing a kit together with quality parts.

Stock 5.7" GM rods - $20
ARP 383 rod bolts - $65
Speed Pro pistons - $230
Hasting cat piston rings - $15
Eagle 3.75" stroke crankshaft (internal balance) - $231
Damper and flexplate kit - $125
Clevite 77 high performance narrowed bearings (mains and rods) - $100+
Balancing - $250
Install and rod resizing - $80

Total=$821


It still ended up being about the same price as a kit and having it balanced.
 
#17 ·
Terrific. I'm glad the old home-balancing brew worked for you. You had a balanced crank, and knew the weights and distribution of the original rods, so upgrading to the scats was pretty straight forward. Still -- Good work, and best of luck.

PatM
 
#20 ·
Lunati used to make a nice, fairly low cost rod, forged of 4340 right here in the good ol' USA. It was very light in weight, and was called the Streetrace rod. I used these in my engine. They ARE horsepower limited, however the consistent American quality of the alloy steel should make them pretty reliable. Does anyone know, does Lunati still make the Streetrace series rods? Here in the states?

PatM
 
#21 ·
Rods, like the GM rods what are they're limits after resizing and good set of ARP bolts ?

Scat and Eagle are they just crap ? I have used both brands, Eagle H-beam in a competition engine and they have been in that engine for several years and still doing fine, came with a balanced kit I bought from World.

I remember one build, high reving 327 I got my self a set of Trick Flow 4340 steel rods, that engine was rpm abused many seasons then I finally sold her and she is still running strong 11 years later.

anyway when I was about to start my last 327 build I contacted Trick Flow and asked them if they were still making them, no was the answer. Because of Scat and Eagle I was told, or were they just not good enough ?

So if good set of GM rods are better than Scat and Eagle and someone needs to go to stronger than GM rods what are your recommendations if my goal is 500 hp ? GM ?

I actually thought Scat was good quality and the same for Eagle but have heard some bad things, not experienced yet..

Man I am going in circles.. :drunk:
 
#22 ·
IMO, you can increase your odds of coming out fine by sticking w/Scat, or even Eagle than going to PC. I'm not as convinced as some are that PC has as 'good' of a QC as the others.

Part of the equation is where you get the parts from. I'll spend a little extra just to deal w/the bigger mail order outfits, just because there no problem w/returns for the most part.

Good luck.
 
#24 ·
I'm a little late, but here is my .02. I have a set of the procomp 4132's in a circle track motor. I didn't buy them and honestly I wouldn't have, but they came courtesy of a sponsor so I ran with them. Now, the only thing I did with these rods was upgrade the rod bolts to ARP's and verify the sizing of the rod. The set up came with a set of AFR 200 heads, 13.5:JE pistons, a 43# scat crank and a full solid roller set up (.650/.650). I have beat on this car for 3 years, commonly turning 7500-8300 rpms (depending on the track). I run short track so you are on and off the throttle constantly. I have had absolutely no problems! I tear the motor down mid season and during the offseason, the bearing look fine each time. Now thats not to say there isn't a bunch of bad procomp stuff out there, but for me, it has worked. In a street motor, I would have no problem with the PC rods, I would highly reccomend changing the rod bolts, and having a michinist look them, but I would do it. I have some expirience through my time at Summit and motors i have built for customers with alot of rods; eagle, scat, carrillo and oliver and based on QC alone, you get what you pay for. But lets face it, we always dont need a $1500 set of rods to get the job done. Words of wisdom, are ignore the mfgs ratings (there are too many variables to say "x rod will handle x power)! Get a rod that you are comfortable running (if you have ran eagles with good luck, stick with them)! Always pay a little extra for the rod bolt upgrade! and Always verify the sizing! I don't care who made the rod, check the sizing.
 
#25 ·
Scat vs Procomp vs all other suppliers

Dear Gents,
I think allot of you are being confused with manufacturing in China and the US.

Most Manufacturing occurs in China and the amount of finishing happens in the US. Scat does more finishing here, Manley has production in China, CAT, Procomp, and many of the others also have production in China. Ford, GM, Dodge etc all have overseas manufacturing.

It all comes down to finishing - Finish it here and the quality will likely be better. But not always - a Machinist recently told me he has ordered 3 BBC cranks and the Number 5 Journal is always tight.

Sound like QA at Scat needs to be tweaked. The human factor.

Consider the facts and the reality - if you are building a engine, do it right and hire a Machinist who knows their stuff.

Backyard engine builders make mistakes because it in not their profession.
 
#26 ·
Well 2Cool, the original post is 5 months old but I will make an exception just so I can challenge your statement about "backyard engine builders"

I was a Police Officer for 33 yrs. and during that time on my days off I built a lot of engines for myself and a few friends. I never once built one in my "backyard", they were always assembled in my clean garage/shop. I did my research, chose the right parts combination for the application the engine was intended for, had a GOOD shop do the machine work.... and built it.

Never had a problem...but I will admit, "some folks just don't need to be messin with engines". I'm assuming they are the one's you're eluding to because there's a bunch of non-professional guys in this good old country...and Canada that can build a healthy, reliable engine.
 
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