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Who is using the front set of holes for the engine crossmember?

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by mcmlxix, Jun 16, 2003.

  1. mcmlxix

    mcmlxix Registered Member

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    I have a 1970 K5 that I am swaping out the 350/sm465/np205. The engines already gone. I have a TBI350/700r4/NP208 out of a 1988 K5 Blazer donor truck. I want to use the two forward mounting holes for the engine crossmember. I think the 700r4/208 are longer then the SM465/NP205 and can use the extra space.

    Has any one used the forward mounting holes for the engine crossmemeber?
    ( why are they there? 6 cyl application?)

    Are there any clearance problems for the oil pan to engine crossmember?

    I will be using the trans crossmember out of the 88 K5 and making my own holes anyway. (I don't think the stock holes will line up any more)

    Any input or <font color="blue">measurements</font> would be greatly appreciated.
     
  2. POFF

    POFF 1/2 ton status

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    I think the forward holes are actually there for trucks with automatics.
     
  3. mosesburb

    mosesburb For Rent Premium Member GMOTM Winner

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    Mine had an A/T from the factory and used the rear holes. The firewall needs only a little bit of modification to clear a big-cap HEI. You shouldn't have to do much at all/if any to make the small-cap dist of the TBI setup work. In its original form, the module pointed roughly towards the rear of the vehicle, but you can rotate the dist one direction or another so the module points to the side instead of to the rear and move your plug wires around to make a different post #1. I did this years ago on my Nova that I converted to TBI, and it worked great--no firewall mods necessary.
    Good Luck!
     
  4. POFF

    POFF 1/2 ton status

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    It's been a while since we researched it. Maybe it was the front holes are for TH400 trucks. I've heard of people fitting HEIs in with the engine back.
     
  5. mcmlxix

    mcmlxix Registered Member

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    Someone beat the crap out of the fire wall with a ballpeen hammer to clear the HEI. I have decided to put a 2" body lift on it so it wont play a big part it in fitment of the HEI. I am now more concerned with the length of the 700r4/np208 vs. the sm465/np205 I took out. If I could use the forward holes I hope to make up for the longer automatic setup, or at least some of it.
     
  6. mosesburb

    mosesburb For Rent Premium Member GMOTM Winner

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    If the firewall is already "clearanced" for the big-cap HEI, you should have no problems fitting a TBI small cap in there. I had a big block with an HEI in my Sub, and it only required a minor amount of modification to clear the big-cap HEI. If yours requires more, you may want to check the frame for straightness. Mine was bent from normal usage, and my frame guy said that these trucks, over time, bend the front of the frame up starting at the body mounts under the cowl area. A quick way to check is to look at your door to fender gaps. If they are real tight at the top and more open at the bottom you may want to have your frame checked by a reputable frame shop. Once I got mine straightened, my HEI clearance increased dramatically.
     
  7. R72K5

    R72K5 Banned

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    remember that HEI was not available yet and wheelbase of all models of trucks increased by 4.5" in which helped alot with firewall HEI and big block clearance for 1975 and for new availability of big blocks in the 4x4's
     
  8. mcmlxix

    mcmlxix Registered Member

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    Re: Engine cross member, two sets of holes, moving it forward, what issues

    any one have any measurements of the length of a 700r4 / np208 combo?
     
  9. JIMs70K25

    JIMs70K25 1/2 ton status

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    I believe the front holes are for a truck with an inline 6.
     
  10. bouncytruck

    bouncytruck 1/2 ton status

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    I think the holes are there for the 6 cyl &amp; 2wd trucks. They moved the engine back on the 4wd so the front drive line could be as long as possible. This is also why there are different fan shrouds for the 2 wd &amp; 4wd trucks/blazers.
     

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