Factory rods BBC
 

I'm getting closer to assembling my 427 bbc. I have a concern about the rods that I have. They are factory BBC truck rods with ARP bolts. I'm going to be spinning this at 6100 rpms. The longest I may have the boat at this RPM is going to be for no longer than 3 minutes. Are these rods good enough for this or should I really go for something stronger and lighter like a manley h rod? The crank is a forged GM crank and the pistons are Forged Speed Pros. Money is a factor so if I don't need to replace these I'd like to use them. But on the same hand I don't want to be cheap and destroy the engine.

Which rods are they? is their a dimple on them? what size are the rod bolts,3/8 or 7/16?

There is no dimple. These are the "thumb" rods that are used in trucks. They are ARP 3/8 bolts. I want to play it safe on this part but on the same hand I don't want to waste money if what I have is fine.

You need the Dimple forged rods with 7/16 ARP bolts. or a set of aftermarket ones with 7/16 bolts

I would be hard pressed to use those stock truck rods for 3 minutes at 6,100 RPM's. Then again, 3 minutes seems like a long time for most anything. You will always worry about them. I would change them out and be safe. If they go at 6,100 RPMs it will be a lot more expensive.

I don't think the dimple are much better. I know I've read that you can push them up to 7K but that for seconds. Three minutes is a long time at 6100, i do agree with that. What do you guys suggest? You have to remember a 427 spinning at 6100 is WAY different that spinning a 496 at 5500. 427's like to rev, but on the same hand I want to build this right the first time.

Get the forged HBeam rods.

:daz:3/8 rod at 6100 equals KABOOM.7/16 is a must,if you plan on 500 hp or more,buy some h beam rods.as they say SEE
ME KNOW OR PAY ME LATER.

Ok so ditch the rods. Are the Manleys over kill? They're rated for 8000 rpms and 900 hp. I'm planning on 550 and 6100 rpms. Any suggestions?

You can never have overkill on rods or crank. Don't skimp and get Eagle H Beams--> They will stick through the block just like a stock rod if not easier. my bilge pump pumped more oil than it did water when we used Eagles rods, and the sound of a rod breaking at 5500+ rpm is interesting, and expensive, get the good sh*t, it'll last through several motors.

end,
For your use and budget, I would buy a set of either Eagle or Scat I beam rods. Just make sure to have your machine shop check the big end for size and roundness, about 1 out of every ten sets might not be quite right. They can be had for less than $290 I think I sell the Scat ones for right around $280. They have 7/16" ARP cap screws and will last forever in a 427.

The H beams would be a good choice if you plan on any additional upgrades at a later time.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Hey Mike,
Who is balancing your rotating assm. You'll be fine with a set of GM 7/16 rods with ARP's. Unless you have a good source on the Manleys. The Manleys wouild work well and would probably be a little more insurance but I think you'll be fine. I ran one of my old boats with the 3/8 rods with ARP's and a good balance job. Ran it hard all the time and never threw a rod. Be sure and check all your clearances.

You may want to back that 3 minutes down to about 2 1/2 minutes, LOL... or at the very least be sure I am somewhere within a towable distance. I am a terrible one on giving advise to get out of the pins though. I run everything hard. Pull it down and go through everything at the very least every other season. Bearing are cheap.

John-
Everything was already balanced from A Team Speed shop in Tinley Park, IL... I was talking to an engine builder last night and he told me in no way run my rods at 6100. He said they are strong but to heavy for that RPM. He suggested the manleys. I found a set for $505.00 which is a good deal, but on the same hand $280 for the scats I like even more. I'm just not sure about chinese rods? It just stinks because now everything will need to be rebalanced. Any suggestions on who to rebalance the assembly around here?

I would find out how many grams each manley and scats weigh and go from there. More Power Racing would be a great place who could help you out on the balancing. They know me well there. Perhaps you could take a little weight off the scats to measure up the same weight. Not for sure on that. Just curious how close the GM 3/8 and the others are in weight. More Power is on M-37 just north of GR near 9 mile rd.

I'm not really a jap man so the more I think about it you might want to pay the 225.00. I don't know if there steel is any better or worse to be perfectly honest. I do know there are a lot of those rods running around out there though.

I hate to say this, but I was searching on some of the "hotrod" sites and there was several guys claiming that manley lower priced rods are chinese slugs with the machining done here which is what scat also does. I do know that eagle rods are junk, but it seems that the scat are good as long as you have them inspected. I would do that with the manley though as well. Seems like the APR 2000 caps are the way to go with either.

Fixx
 

one thing to consider,are your pistons full float or press fit?
if their press fit and your looking to go to a h beam style rod your going to have to replace your pistons to floating...

check out k1 rods,their made by carrillo

http://www.flatlanderracing.com/K1-rods.html

Go figure. It seems like I read something like that as well. It was an article having to do with Ohio Steel. As long as you have it balanced by a reputable machine shop and feel confident with your build I wouldn't worry about the rods letting go. 6000 to 6500 R's still are not real high. Considering your using a 4 bolt main block and steel crank. Many old timers use to run BBC's over 7000 and that was using GM rods. I realize us boaters put engines to the test with the constant load and hi rpms but...

If you can run a 454/330 for endless miles WFO and have no problems at 4900 you'll be fine. I ran scat rods in my 496's and plan to run them about 5800. I'm more concerned about my drives than anything.

Keep in touch and if you need anything while your up north just email me or call. Where are you putting your engine together? Word around the campfire is, Hugh Rollins (well guy) was wondering what in the hell was running over here near the golf course recently... Can't wait to run the boat next summer.

The K1 rods look like a great deal. I may go with those.

Thats funny- I'm sure old Hughey was wondering what was going on. FYI stay clear of the well truck, no brakes on that thing.

As for the motor, I think I'm going to put it together at my brothers, he has everything I need except for the tool to measure the push rod length... I'm going to be up here a lot this winter. So if your going to fire the boat up agian let me know. I'd like to hear that thing run.

fastdonzi,i have used eagle rotating assemblys in many marine applications[supercharged]800 to 1000 hp,have not seen any failures.i always use the arp2000 bolt for marine application.imo the eagle rod with arp2000 bolt spinning 6000 rpm with 1000 hp is not a problem.

endeavour,i have a set of used manley h beam rods with arp bolts i will sell you.400. plus shipping.they came out of a 509 that was upgraded to a 540.

Mike-
I'd be interested in your rods but my pistons are press fit and I don't want to replace the pistons. Is there a way to convert either that is friendly on the wallet?

Fixx
 

impossible,the rods have a bushing in them and press fit don't,..look for a good set of I beam or dimple rods with arp rod bolts,just make sure you prestretch the rod bolts before assembly.

Thanks for the info. I really like the Carillo K1's. I think I'm going to go that route. For 299.99 that's a great deal.

end,no cheap way,but keep this in mind,YOU GET WHAT YOU PAY FOR.good luck with your build.:coolcowboy:

If you are planning turning over 6k in your boat, don't worry about those rods so much, we have drag raced 3/8 std chevy B/B rods in several engines with many many runs spinning them to 65-6800 all the time, never a issue. What you need to concern your self is the drive....that will fail first at that RPM, my advice is to set the engine to operate at a max or 55-5700, things will work much better...Rob

Fixx
 

Spend the extra coin on the arp 2000 rod bolts..My friend chris @ nelson's racing engines in fl uses k1 rods all the time and never had any issues..supposedly merc 525's have the h beam style k1's in them..so I'm told.

a friend ran his stock GM rods to 6K rpms for several seasons without any issues but I seem to remember 5800 is about max for them. After he sold the boat I think a rod let go so it's pushin it!