Connecting Rod Questions

[zraffz]

Please tolerate my stupidity, I have a lot of questions lol.

Long story short, I bought LT1_8u's Trickflow 21* heads. I plan on sending them out to Lloyd Elliot at some point and seeing what he can do with them to better accommodate my build. I want to put them on a 383. I'm hoping he can open up the runners to 200-205cc's. I plan on making the car mainly a track car with minimal street time and topping the build with a 150-200 shot of nitrous.

My brother wants to get me connecting rods for the motor I'm piecing together as a Christmas present. I've been reading a lot trying to get information to do it all the right way the first time.

My questions:
6" H-beam or 6" I-beam rods? If H-Beam, will the machine shop have any problems making them fit?
My options seem to rather be 3/8" ARP 2000 rod bolts or 7/16" ARP 8740 rod bolts; I've read the 2000s are stronger, but I can't seem to get them on a 7/16" diameter bolt without spending an extra $200.


Out of the 3 rod choices which one is ideal for my situation? Or can I get a link to a better one in the same price range?
http://www.ohiocrank.com/hbeam_rods.html Part # H6000
http://www.summitracing.com/parts/SCA-2ICR60002000/
http://www.summitracing.com/parts/SCA-26000716/

[sweetbmxrider]

Compstar 6 inch i beams.

[S.J.SLEEPER]

^ :stupid: ^

[zraffz]

Compstar 6 inch i beams.

Do they make a 6" I-beam? I looked for a while and only found h-beams.

[sweetbmxrider]

http://www.cnc-motorsports.com/product.asp?ProdID=27941&CtgID=27939

[zraffz]

Eh I can get my brother to half that with me but it's still a lot of money lol. Probably my best bet though, huh?

[sweetbmxrider]

Ya. The 3/8ths scat's have a 2.000 inch rod journal by the way.

[zraffz]

Ya. The 3/8ths scat's have a 2.000 inch rod journal by the way.

Oh I didn't notice that.

I might but myself a New Year's gift. Any suggestion on a crank? I was looking at one from Ohio Crank or the Lunati Sledgehammer but I'm open to suggestions. You guys know better anyway. (Please can we keep this one a little cheaper than the rods though lol).

I want my bottom end parts to be ordered by February so I can send the motor to the shop.

[sweetbmxrider]

Well I would say compstar but they stopped making the 1 piece rms cranks. The lunati and ohio cranks are both good pieces. No personal experience with them but I wouldn't hesitate to get one.

[LTb1ow]

Sledgehammer crank is no longer made FYI

[zraffz]

Sledgehammer crank is no longer made FYI

Is the ohio crank 4340 forging for $495 any good? or the promax (assuming its 1 piece rms) for $570?

[LTb1ow]

I have no idea what kind of build this is, but if you are trying to do it cheaply, re use the stock crank.

[zraffz]

I have no idea what kind of build this is, but if you are trying to do it cheaply, re use the stock crank.

Doing a 383, plan on having LE port my trickflow 21* heads to whatever he thinks is best (probably a 200+cc runner if he can). Mainly track car with minimal street time (if any). Oh and a 200 or 250 shot in the future after the rest of the drivetrain and suspension is done.

I'm in no rush to have it together. I'd rather do it right the first time but at the same time I don't think I need to spend a thousand bucks on a crank.

[coolmanvette75]

If ur going to spray that much, I wouldn't cheap out on the crank. Callies compstar (if you can find one) and dragonslayer are both good choices. My dad has a lunati crank in his sbc in his vette and it had held up to 7k rpm since 03

[Slow Z]

I really don't see the purpose of using all those fancy top dollar rods and cranks when in the end you're throwing them into a stock block. I'd personally buy both Scat rods and crank. I've been beating the crap out of my cast steel scat crank and 6" I-beams for years without failure and according to those ET-to-HP calculators I'm making just shy of 700HP at the crank.

[LTb1ow]

I really don't see the purpose of using all those fancy top dollar rods and cranks when in the end you're throwing them into a stock block. I'd personally buy both Scat rods and crank. I've been beating the crap out of my cast steel scat crank and 6" I-beams for years without failure and according to those ET-to-HP calculators I'm making just shy of 700HP at the crank.

Becuase there is no other block alternative.

[sweetbmxrider]

Becuase there is no other block alternative.

This.

[LTb1ow]

Although, to be fair, you COULD buy a GM LTX perf block if you can find one and afford it.

[Blacdout96]

Or, could perform a sin and wander into LSX land lol.

[LTb1ow]

Or, could perform a sin and wander into LSX land lol.

Well if he already has rods and a crank, a aftermarket dart SBC block would be better :mrgreen:

[Slow Z]

Becuase there is no other block alternative.

I'm saying why buy a rotating assembly that is stronger than the block it's going into? There is really no point in wasting your money when at any moment the block could fail and destroy all the fancy crap inside it.

A "cheap" Scat Forged crank and I-beams will be as reliable as the block they're in and cost waaaaaay less.

[coolmanvette75]

Then I guess people like Tony Shepard are stupid for stuffing their weak stock block with expensive parts and running 8s then ;)

[Slow Z]

Then I guess people like Tony Shepard are stupid for stuffing their weak stock block with expensive parts and running 8s then ;)

Ok, so does the OP intend on filling his block with cement and throwing some splayed billet main caps in there as well cause I bet not a single LT1 guy running in the 8's has a factory unaltered block and if they do they are being very ballsy.

[LTb1ow]

Factory unaltered as in...?

Yes the very fast guys run filled blocks, but a lot do not, and splayed mains are just a safe insurance when you are stuck with a 2 bolt main block.

Dunno why this is a hard concept for you.

[zraffz]

I understand what he is saying. 99% of the street/strip cars do not have filler in them. The block is the weak link, even if I used a crappy aftermarket forged crank.

No need to argue. Figured out what I'm doing. Stock crank, h-beam rods, mahle pistons and just doing a 355 with a 150 shot. (Oh and I guess I'm lucky; I have a 4 bolt block).

[Slow Z]

Factory unaltered as in...?

Yes the very fast guys run filled blocks, but a lot do not, and splayed mains are just a safe insurance when you are stuck with a 2 bolt main block.

Dunno why this is a hard concept for you.

I'm just making up HP numbers here but let's pretend a stock LT1 block is capable of safely handling 600HP and beyond that it may last 1 pass or it may last 2000 passes... Either way it's a gamble each run.

Now let's assume you buy a rotating assembly that is capable of handling 1200HP and put it inside this block... What is the point? Regardless of how much HP your crank, rods, or pistons can tolerate the fact is you still have them in a block that is unsafe at half the HP level the rotating assembly is. Therefore you might as well just buy the cheaper stuff that is rated around the same limits as your block because you are simply wasting your money. The saying "a chain is only as strong as it's weakest link" applies here.

I'm not saying you can't go fast with stock parts - I and countless others have done it on a somewhat reliable level but it's still a gamble each pass

[sweetbmxrider]

Lt1 blocks usually start grenading around 1000hp unfilled.

Why H beams?

[Pampered-Z]

Baxter ran his LT1 for years, 383, 18-20 Lbs of boost, he had documented 1,000+HP on the engine dyno and wasn't afraid to throw in on the chassis dyno and record 900+ at the wheels! This was a full weight car that still had the power options and convertible top and ran low 9s and never had a block failure, Frosythe's 381 CI LT1 is in the 900HP range with twin 175 shots ( reason it's a 381, to give a little extra for the side load on the cylinder walls). Again, full weight car, no failures. Neither are using block filler and spin into the mid-high 7,000 RPM range.

Quality crank, rods, pistons, bearings, sprayed caps and a good builder is what is needed. The LT1 is nothing more then any other SBC with reverse cooling. As long as you have the block checked and make sure it's a good one you should be fine.

The after market blocks we chased companies to build for years was really for more CI and taller deck, web/main strength and block flex really isn't an LT1 short coming except for the really hard core. The guys running deep into the 8's are suppose to be spinning well over 8Gs, I've heard some had issues with flex/bearings walking, there use to be stud girdles out there for the LT1s to fix this. But even without, the blocks aren't falling apart.

Most of the failures you going to see is in the crank breaking or rods twisting,. Power adders put allot of stress on these parts.

[zraffz]

Lt1 blocks usually start grenading around 1000hp unfilled.

Why H beams?

I could spend $800 on a set of I-beams that could hand 450ishFWHP and a 150 to 250 shot or I could spend $400 on a set of h-beams and have the same end result.

[LTb1ow]

Except I would bet the H rods are heavier and require more clearancing to the block to fit in.

[zraffz]

Except I would bet the H rods are heavier and require more clearancing to the block to fit in.

On a stock stroke motor? I would bet they require no clearancing.

[Pampered-Z]

I could spend $800 on a set of I-beams that could hand 450ishFWHP and a 150 to 250 shot or I could spend $400 on a set of h-beams and have the same end result.

:facepalm: Shouldn't you be shooting for Rear Wheel HP?

[Blacdout96]

probably ment FlyWheel hp.

[zraffz]

:facepalm: Shouldn't you be shooting for Rear Wheel HP?

No... I didn't tell you?! My Z28 is front wheel drive. 8-)