Connecting rods

-
3

340Dust-her

Well-Known Member
Joined
Mar 14, 2008
Messages
238
Reaction score
1
Location
Fresh meadows ny
I'm in the process of purchasing some bottom end parts for a 340 rebuild. What are your thought on scat I beam rods weighing in at 595 grams? They're forged 4340 and new. Running just above the $300. Good investment? Cruiser/ weekend strip
 
Def stock stroke with .030 overbore. I prefer forged pistons since I'm extremely happy with my speedpro on my sbc. If there's another brand that works well with the mopar crowd please let me know. I want to recondition the stock crank and maybe cut some weight off of it.
 
Those are the SIRs? I would make sure they are cycled and checked but they'll be fine. A stock rod with good bolts is heavier but will last fine too. Mopar rods are almost never a problem. With factory strokes they can go to 7Krpm+ with good bolts in them.
 
Reconditioning the rods will prob cost half of lightweight forged units may cost. I guess you could say that I'm going for the cost effective approach. What do stock rods usually weight? Eagle has a set which is basically the same but with 618g weight and runs $295.00.
 
340Dust-her said:
Reconditioning the rods will prob cost half of lightweight forged units may cost. I guess you could say that I'm going for the cost effective approach. What do stock rods usually weight? Eagle has a set which is basically the same but with 618g weight and runs $295.00.
Click to expand...

Better price on same rods for you...........$259.00

http://chucker54.stores.yahoo.net/eagchryssbib.html

I think by the time you recondition the rods and put good hardware in them you would be better off with NEW rods in my opinion. Remember those rods are 40 years old......JMO
 
I think by the time you recondition the rods and put good hardware in them you would be better off with NEW rods in my opinion. Remember those rods are 40 years old......JMO
Click to expand...

I agree 100%..
 
Mad Dart said:
Better price on same rods for you...........$259.00

http://chucker54.stores.yahoo.net/eagchryssbib.html

I think by the time you recondition the rods and put good hardware in them you would be better off with NEW rods in my opinion. Remember those rods are 40 years old......JMO
Click to expand...

Thanks. As far as rods bolts go they say
APR 8740 wave Lok ™ 3/8" rod bolts (190,000 psi)

APR? Or ARP?
 
340Dust-her said:
I was looking at Mancini website and they're 2 different forged pistons from sealed power. One is:
http://chucker54.stores.yahoo.net/340comdis18s.html
other is:
http://chucker54.stores.yahoo.net/340comdis18s1.html


it's a $100.00 difference. Is it worth it? Dosent state if either are dome, but looking for flat top. Want to run on pump gas,Street cruiser, weekend strip(long road trips)
Click to expand...

First set

Stock deck 9.60 3.31/2=1.655+6.123+1.829=9.607 puts you out of the hole .007

The second set of pistons will put you out of the hole on a stock deck height .018.......Stock deck is 9.60 3.31/2=1.655+6.123+1.840=9.618

You using open chamber heads?? cc's ??

Get all your information together and put it into this calculator.

http://www.kb-silvolite.com/calc.php?action=comp
 
I still have to do my research, but I'm going to stay with the stock heads( no milling nor porting the chamber. Stock cc, although I'm not sure what it is. Obviously it'll be reconditioned. It's a stock 340 from a 68' barricuda, so it must be a "j" head?
 
340Dust-her said:
I still have to do my research, but I'm going to stay with the stock heads( no milling nor porting the chamber. Stock cc, although I'm not sure what it is. Obviously it'll be reconditioned. It's a stock 340 from a 68' barricuda, so it must be a "j" head?
Click to expand...

I am not 100% sure but I think those heads are 68 to 70+cc.

Does anybody else have the answer to the CC question for these heads?

To be exact you should have them CC'd at the shop.
 
I think everyone would agree that 4340 is better steel than 5140..........
 
'68 should have "X: heads and they (if never touched) should cc in the 74cc range. If you want to make power with this engine, the long block should be blueprinted. SRP makes nice piston and not too pricey. Otherwise Diamond would be my choice. But for your use, I wouldnt use forged pistons unless you had some other reason (boost or NOS in the future). The hypereutectics would be fine and a bit lighter than the oldschool forged.
 
moper said:
'68 should have "X: heads and they (if never touched) should cc in the 74cc range. If you want to make power with this engine, the long block should be blueprinted. SRP makes nice piston and not too pricey. Otherwise Diamond would be my choice. But for your use, I wouldnt use forged pistons unless you had some other reason (boost or NOS in the future). The hypereutectics would be fine and a bit lighter than the oldschool forged.
Click to expand...

I've heard great things about you so I will take your advice into consideration, not to take anything from anyone on this board. You guys have been so helpful. So far this is my setup. Kb hypereutectics pistons(4.070 bore)with 4340 rods, refurbish crank. Rebuild the x heads with stainless valves, lunati 60403 cam with new springs. Rpm dual plane manifold and 650 dp carb. 3000 stall PTC converter with 904 transmission and 3:55 gears(will go to 3:91) in the future. Stick with 1.5 rocker arms. I'd like to get 10:1 compression. With the 74cc heads what thickness and brand headgaskets do you guys suggest? After the gaskets, I think I'm done, lol.
 
70aarcuda said:
I think everyone would agree that 4340 is better steel than 5140..........
Click to expand...

Thanks for the link to the SCAT RODS!!!.......Just bought a set for myself!! Doing another 410 Stroker in a few months. Working on a 318/349 Stroker now. Brian at IMM Engines is doing the machine work. Just dropped of the assembly and block this morning!!
 
I like Fel-Pro gaskets though in truth, any gasket set on a clean surface and a flat head deck will do the job. Mr. Gasket Ultra Seals I like a whole lot too.

My advice for gasket hunting is to know what you want from your gasket. In terms of bore and thickness. At .030 plus the 4.04 = 4.07 bore, the gasket you need must clear the 4.07 bore. Now theres the bore size.

Thickness comes in many sizes. Alot of the thickness will depend on where the piston sits in the cylinder. Above, below or flush (Zero deck) and how close you want to run the piston to the head.

For a street car, .040 is fine. You can get tighter, but theres no real reason increase the quench. Unless you want to. I've run a .039 quench in my 360 Edelbrock headed, zero deck piston height engine with stock rods.
 
Very cool. Thanks!

I really don't trust summit when it comes to ordering parts since some of the parts listed for a specific application never matches. When it comes to main bearings, it's prob best to wait it out till the machine shops inspects it? There are .010 and .020. Versions.
 
Thanks for the kind words. There are many decent guys here tho and I'm sure they'll chime in. In terms of your plans they sound fine. I think it will be the details that make it "good" or "great". By that I mean any piston you chose has the same issue with the block being too tall. So you want to make sure it gets machined properly to get the pistons where they need to be. Make sure you and the shop recognizes that the parts choices are the small deal. Machining right and fitting them together to make them work right is much more important to power production than cast or forged or the name on the cam. The basics I'd say are keep it the hyper flat top and get things set to be no higher static compression than 9.5:1. Keep the cam's intake duration between 225-228°@.050 and it will be fine on pump fuel and stiull reasonably torquey. I'm not a fan of double pumpers on street cars and I'd run a 750 dry flowed cfm on it. That's a highly debated deal but that's my take on it...lol
 
The Scat Pro-Comp's also use an ARP 8740 7/16" cap screw vs. the Eagle rod w/ a 3/8" cap screw.

A better rod for alittle more dough. Mine checked out with no problems, I have read there were some machining/QC issues in the past with some Mfg'rs parts.


I like to check everything myself.
 
You must log in or register to reply here.
-

Back
Top