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.

Compression test, Vortec Time?

Discussion in 'The Garage' started by Hardcore, Jun 2, 2003.

  1. Hardcore

    Hardcore 1/2 ton status

    Joined:
    Apr 25, 2003
    Posts:
    458
    Likes Received:
    0
    Location:
    New Orleans, LA
    OK, this weekend I decided to see what my 1990 350 with 150K miles had left in it. It runs great and doesn't leak oil, plenty of power. It lets out a puff of smoke when it starts after sitting for a couple days but I'm sure it's the valve seals. My compression test showed all cylinders (without oil) were around 180. The worst being 175 the best being at 185. I think that's pretty good. /forums/images/graemlins/thumb.gif

    So now the question. Should I go ahead and put Vortec heads, a cam, and intake on this old block. I'm debating over whether or not to go all out and put in the crate motor but seeing as how my bottom end is in great shape I may be able to get a couple more years out of it.

    What do you guys think?
    ANy recommendations on a cam for a TBI 350?
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    I'd be pretty hesitant to put new heads on an "old" motor.

    The way I look at it, with that many miles, you are going to need to pull it/rebuild it in the not too distant future (in engine years : ), and putting new heads on, then having to pull them later, is kind of pointless.

    I know if I pulled heads off of a motor, I'd pay to have them checked out before re-using them (warped, etc) and thats additional cost.

    If it runs good, put $20/month (or whatever you can afford) aside, and build a motor from the ground up now. If you get it done before yours fails, great, you sell it and recoup some of the buildup cost, if it fails while you are building it, you have at least started, or have the money saved up.

    If the motor has been really well taken care of, there is no reason it can't go 200,000 miles or more, but you really have to expect the cylinders to be opening up, the timing chain starting to get sloppy, bearing clearances starting to increase, and so on at 150K.
     
  3. Hardcore

    Hardcore 1/2 ton status

    Joined:
    Apr 25, 2003
    Posts:
    458
    Likes Received:
    0
    Location:
    New Orleans, LA
    TTT Anyone else?
     
  4. Nitrodrip350

    Nitrodrip350 1/2 ton status

    Joined:
    Jul 22, 2001
    Posts:
    358
    Likes Received:
    0
    Location:
    Centennial, CO
    Well I will tell you this .... I was in the same place you were about 2 years ago. The only problem is I wanted to work on something so I ripped a perfectly good running motor apart to put aftermarket performance parts in her. Really nothing crazy - Streetable Comp 4x4 cam, manifold carb and some low compression heads (Z28 76cc) well it really only took about 6 months to blow the rings out. If you can I would suggest just doing it all at once. 150,000 miles is good, so I know that you probably take good care of her, but you start throwing higher compression heads you may mess up the bottom end in the process. Just my .02 /forums/images/graemlins/thumb.gif .....

    Thanks, Shane
     
  5. Hardcore

    Hardcore 1/2 ton status

    Joined:
    Apr 25, 2003
    Posts:
    458
    Likes Received:
    0
    Location:
    New Orleans, LA
    What would the compression be after Vortec heads? I think its 9:1 now in stock form.
     
  6. Hardcore

    Hardcore 1/2 ton status

    Joined:
    Apr 25, 2003
    Posts:
    458
    Likes Received:
    0
    Location:
    New Orleans, LA
    BTW the 150,000 miles is mostly highway. Where does the 180 psi fall in the range of compression. Fair, Good, or Great
     
  7. blasterD

    blasterD 1/2 ton status

    Joined:
    May 24, 2003
    Posts:
    410
    Likes Received:
    0
    Location:
    Anchorage Alaska
    I'm not sure of your stock compression, but with flat top pistons and 64cc Vortech heads you should have 9.6:1. Your stock TBI heads are 60cc so you would actually lose compression with the head swap
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    Stock 350 TBI heads at 60CC? I really find that hard to believe. Data to back that up?

    305=58CC, but I thought (early) 350 TBI heads were 76CC.
     
  9. MousePowrd

    MousePowrd 1/2 ton status

    Joined:
    May 7, 2003
    Posts:
    215
    Likes Received:
    0
    Location:
    Saginaw, MI
    Leave the 350 alone and put the $1000 or so you have now into CD's at the bank. Keep saving and in a year or so you will have the cash for a 383 /forums/images/graemlins/cool.gif
     
  10. blasterD

    blasterD 1/2 ton status

    Joined:
    May 24, 2003
    Posts:
    410
    Likes Received:
    0
    Location:
    Anchorage Alaska
    I cant find any hard data but, P.A.W. sells rebuilt TBI heads for 87-94 trucks and lists them as 60cc. BTW the Edelbrock TBI replacement head PN 6085 is 60cc also.
     

Share This Page