what do you guys think of this. right off the web site not for the LT1

S/B Chevy Superlight Kit

• SCAT 4340 Forged Superlight Crankshaft
• with SRP Flyweight Pistons

• New SCAT 4340 Forged "I" Beam
• Connecting Rods

• Available in all Strokes with Childs &
• Albert/Total Seal Dura-Moly Rings &
• Clevite 77 High Performance Bearings

what is the difference between h beam and i beam rods, i have looked for an answer but came up with nothing.
this will be a blower app with a 15# pulley on a street car. im just looking to get some ideas together as far as what to buy. thanks for the help. i dont have prices i will call them tomorrow, just needed opinions.

 

This is an inappropriate rotating assy for a blower car, as I am sure SCAT will tell you. The lightweight pistons will not be strong enough. I am also a little leary of the "superlight" crank, though again SCAT will be the best source of information on this. As far as I vs. H-beam, all else being equal, the diferences are trivial. I would not choose one rod over another based on that.

Rich Krause

 

thanks for the reply rich, i just wanted a few opinions before i spoke to a rep at SCAT. but why would they be forged pistons? for nitrous, whats the advantage if they may not be strong enough in your opinion? like i said i just want to find out what others are running so i can make a few good choices. when you first did your 383 whos parts were you running.
as far as heads go are 210 AFRs way to big for a stret car. obviously im still researching this but figured id ask.
goals: ~550 RWHP, nice running car, 383ci with a d1sc.

 

The "flyweight" pistons are light weight pistons designed for relatively low hp NA motors. The are simply not strong enough for forced induction. The SRP catalog states "Designed for Late Model Stock, two Barrel applications up to 400hp". There are SRP pistons that are suitable for forced induction though. My first motor used Wiseco pistons, a Callies crank, and Eagle rods. I would not recommend the Wiseco pistons. The other parts worked well.

My original combo used stock heads, then I went to out of the box AFR 195cc LT4 castings. Now, I am running ported AFR's. A set of ported 190-195cc AFR's are a better choice than the 210cc head for a street car. They will have over 200cc ports after being worked which is plenty big enough for the hp level you are looking at and offer better low speed performance.

Rich Krause

 

at first i wanted to buy an eagle 6" rod but after talking to a few of the guys on here i was persuaded not to. i was told the metal fatigues and the rod bolts rip out. i dont want to be cheap but 600 or more for rods is not in my budget if i wanted lunatti, or manley. any truth to any of this guys.

 

I recommend a 5.7" rod for a blown stroker. You need the extra compression height to allow proper ring land support.

Rich Krause

 

with a 6'' rod the ring land is pushed upwards, thats what your saying correct, i have heard that but i was told that it wasnt a big deal( as long as its forged) BUT what about the shorter rod putting more stress on the cyl wall because it is comming down in the hole farther? DOES this make sence, i have been talking to alot of people and im trying to weed out the good and bad info.

thanks for all your help

 

The piston travel exactly the same distance no matter what the rod length. A shorter rod does produce more side load on the piston. This may increase bore wear. However, blower motors almost always break or get upgraded long before they wear out! In any case, the differences between a 5.7" and a 6" rod are fairly trivial. And OTOH, if you want a 6" rod, just be sure you get "buttons" to support the oil ring where it crosses the pin bore.

Just be sure you are getting a piston designed for boost. The crown will be thicker, the ring lands beefier, and ideally an upgraded wrist pin will be used.

Rich Krause

 

thanks for the info

 

Rich, I know I have asked you some heads questions before, but just wondering what you wouldnt like about having the 210cc on a street car compared to the 195s?


edit: i dont mean at a lower hp level where you mentioned it would affect low speed performance....but more in terms of the higher hp cars like yours

 

Ported 195's will flow better than unported 210's. Once you have the 210's ported, the port volume will be in the 220-225cc range. This will not run too well at low engine speeds due to low port velocity. It's just too big a head for a street SBC. If you had a really big stroker it would be ok, but I think they are just too big for a garden variety 383.

OTOH, I don't know how picky you are about how a car drives. Maybe you would find it acceptable?

Rich Krause

 

sorry I added the edit to my first post while you were already responding rich, but it looks like you got what I was getting at anyway


I for one am probably more willing to accept what others consider unacceptable in my street car. I tend to be the opposite of normal thinking. Ive wanted a roll bar/cage all along, I want 5pt harnesses, I want it to be fairly loud (although ive quieted mine up a bit), Im fine with a lumpy loud idle. It feeling like stock is what is unacceptable to me, the nastier it is the better for me (so long as I get somewhat decent gas mileage, b/c I drive waaaay to much to get poor mileage).