Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Changing rods (maybe)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Andreas, Oct 10, 2000.

  1. Andreas

    Andreas 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    188
    Likes Received:
    0
    Location:
    Sweden
    What needs to be done if I´d want to change my 5.565" connecting rods to 5.7". Got a 350 (completly disassembeled), so I thought "maybe?". If there´s not too much work and cost involved I´d like to go for it. I will buy new pistons later on, either way.

    Andreas

    406cui of pure sh*t[​IMG]
     
  2. ken

    ken 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,244
    Likes Received:
    0
    Location:
    Anaheim, CA
    Don't waste your time. It requires you to totally disassemble your 400, then press off the pistons off the old rods and risk cracking them. Not even worth the thought. Do you routinely rev your engine over 5500 RPMs?? If not, don't change the rods.

    ken
     
  3. Andreas

    Andreas 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    188
    Likes Received:
    0
    Location:
    Sweden
    Ken, the 400 is more or less disassembled, and as I said (wrote[​IMG]) I´m changing pistons anyways. Changing cam & lifters too, in a couple of weeks...and it´d be a shame not to strengthen it up when I got those 350 rods doing nothing useful. I´ve heard the "safe limit" off sb400 is about a thousand revolutions less than you mentioned. Any thoughts on that?

    Andreas

    406cui of pure sh*t[​IMG]
     
  4. ken

    ken 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,244
    Likes Received:
    0
    Location:
    Anaheim, CA
    I've heard 5500 for a 400. Since you have it totally disassembled already, and haven't ordered the special 400 pistons necessary for the longer rods, then by all means install them. Note that the most important thing to do is have the "ARB" style bolts added to the rods, and have them re-sized, and if you can get it done where you're at, shotpeened. These three things will increase the life of the rod five-fold!! (Or thereabouts!) Also note that you have to watch the rod bolt head-to-camshaft clearance, as that's one of the main reasons why GM changed to a shorter rod...to avoid interference with the camshaft due to the long stroke of the 400's crank. Good luck!

    ken
     
  5. Tommy

    Tommy 1/2 ton status

    Joined:
    Feb 21, 2000
    Posts:
    260
    Likes Received:
    0
    Location:
    Alabama
    Definitely run the 5.7 rod. It reduces cylinder wall stress, and seems to broaden the power band. I have gotten used to revving a long rod 400, 7K rpm, but you want do a stock rod that high. Definitely put good bolts in, check your cam for clearance, and you will have to grind 3 rods a little to clear cam, no big deal, most machine shops know what to do. Good luck

    Drive it Like You Hate It!
     
  6. Andreas

    Andreas 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    188
    Likes Received:
    0
    Location:
    Sweden
    You run your 400 up to 7K rpms?....crazy man [​IMG].
    Well, I talked too a few machineshops today, about costs for balancing etc. and I think I´ll do it!!

    Andreas

    406cui of pure sh*t[​IMG]
     

Share This Page