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.

Headers for LT1 swap?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BigBad75K5, Dec 5, 2001.

  1. BigBad75K5

    BigBad75K5 1/2 ton status

    Joined:
    Nov 16, 2001
    Posts:
    164
    Likes Received:
    0
    Location:
    Cincinnati Ohio
    I have a 94 LT1 I was thinking about putting in my Jimmy and was wondering if my current headers will bolt up to the LT1 heads? Also,do they use the same motor mount locations?Thanks
     
  2. 88streetblaze

    88streetblaze 1/2 ton status

    Joined:
    Jun 27, 2001
    Posts:
    314
    Likes Received:
    0
    Location:
    middle of sticks, oklahoma
    the motor mounts off of the car are different but the block does have all of the holes so that you can use the brackets off of you motor.

    as for headers, more than likely your headers will not work, because the lt-1's are an inch wider than the normal 350. that is why it took me 8 sets to finally get a set that works, but any ways give Street & Performance a call, their web site is http://www.tunedport.com/newhtml/newheaders.html

    they where the only ones i found that would work. tell them what you have and they will be able to make a set that works. and their prices and quality is comperable if not better than any of the other sets i tried.

    good luck with the swap, and i hope you have another vehicle you can drive will your jimmy is down. feel free to ask any other questions.




    <font color=blue> If sancho knows what good for him, he best go run and hide. Cause daddy's got a new 45.</font color=blue>
    <P ID="edit"><FONT class="small">Edited by 88streetblaze on 12/05/01 03:47 PM.</FONT></P>
     
  3. BurbinOR

    BurbinOR 3/4 ton status

    Joined:
    Feb 17, 2000
    Posts:
    5,829
    Likes Received:
    0
    Location:
    Oregon
  4. Lonnie

    Lonnie 1/2 ton status

    Joined:
    Dec 5, 2001
    Posts:
    138
    Likes Received:
    0
    Location:
    Pittsburgh, PA
    Not sure where you got that the LT1 engine is 1" wider than a standard 350. It is the same exterrnal dimension...(block &amp; heads) with minor distributor, waterpump/cooling &amp; motor mount differences. FYI I build race/high performance motors &amp; have done quite a bit with LT1 engines. Where was your header interference? If you need any info on these engines feel free to ask. Here is a buildup of my motor for reference <a target="_blank" href=http://www.westol.com/lpavtis/95camaropage.htm>http://www.westol.com/lpavtis/95camaropage.htm</a> Hope this helps.
    Lonnie
     
  5. 2Dogs

    2Dogs 1/2 ton status Premium Member

    Joined:
    May 4, 2001
    Posts:
    3,470
    Likes Received:
    35
    Location:
    Ca
    Does your LT1 have the Opti Spark Distributor? Dont get it wet! No washing or creek crossing etc.... Tough to avoid in a Blazer.

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  6. Lonnie

    Lonnie 1/2 ton status

    Joined:
    Dec 5, 2001
    Posts:
    138
    Likes Received:
    0
    Location:
    Pittsburgh, PA
    You can carefully drill &amp; spot face the intake to mount a normal distributor in the LT1 intake. Also a carbureted manifold is available from GM to fit the LT1 engine.
     
  7. BigBad75K5

    BigBad75K5 1/2 ton status

    Joined:
    Nov 16, 2001
    Posts:
    164
    Likes Received:
    0
    Location:
    Cincinnati Ohio
    Thanks for all the replies.Cool web site,do you recall what you paid for the S&amp;M headers? It looks like the differance is in port designe and the EX ports are spread out a little more than the older designe. I don't have to worry about the time line,whats left of the body is off the frame! LOL
     
  8. BurbinOR

    BurbinOR 3/4 ton status

    Joined:
    Feb 17, 2000
    Posts:
    5,829
    Likes Received:
    0
    Location:
    Oregon
  9. 2Dogs

    2Dogs 1/2 ton status Premium Member

    Joined:
    May 4, 2001
    Posts:
    3,470
    Likes Received:
    35
    Location:
    Ca
    Hmmmmmmmmmmmmm. My Bud has an extra LT1 lying around that I have ignored cuz of the Opti-Crap. Should I reconsider?
    Does anyone have dyno graphs (torque and hp) for the LT1?
    I'll check at corvetteforum.com also.

    I LOVE the power in the Vette but I think it feels extra good because of low gears.

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  10. 88streetblaze

    88streetblaze 1/2 ton status

    Joined:
    Jun 27, 2001
    Posts:
    314
    Likes Received:
    0
    Location:
    middle of sticks, oklahoma
    The 1in wider thing i read in a magazine i can't remeber which one, and that was also the only way to explain why the headers i had wouldn't work, for example headman just started making a set of their normall full length headers for our 4x4 (with the only differance is they are for the d-port heads) on my old 350 they fit perfectly but with the lt-1 one on the driver side the rubbed against the shackles and on the pass side they hit the bump stop for the thrid member. But you always know that there is a possibilaty that i am completly off my rocker about the 1 in thing, but hey if i'm wrong i'm wrong and i don't mean to pass off bad info. but like i said the headers fit fine for the original motor but not the lt-1

    now as for the omni spark ignition, yes there was some initial problems with water getting into the dist. and causing problems but in '96 they added what is basically a vac. line off of the intake and they haven't had any problems since, and that is something that could easily be done to a older lt-1, but you would have to get a new cap that has the ports on it to hook up that line and buy the line because it has a (the word is slipped my mind) that keeps from causing a miss in the motor. and yes it does work, i've pulled apart the dist. in both a 94 &amp; 96 with the close to the same miles and driven in the same areas and the differance is very noticable.

    <font color=blue> If sancho knows what good for him, he best go run and hide. Cause daddy's got a new 45.</font color=blue>
    <P ID="edit"><FONT class="small">Edited by 88streetblaze on 12/06/01 09:58 AM.</FONT></P>
     
  11. BurbinOR

    BurbinOR 3/4 ton status

    Joined:
    Feb 17, 2000
    Posts:
    5,829
    Likes Received:
    0
    Location:
    Oregon
    Ignore it. Then send it up to me!

    Stock it puts out more HP than the original TPI motors.........and I think the torque curve matches it. Very intriguing possibilities..............

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com>www.blazzinor.rockcrawler.com</a>
     
  12. Lonnie

    Lonnie 1/2 ton status

    Joined:
    Dec 5, 2001
    Posts:
    138
    Likes Received:
    0
    Location:
    Pittsburgh, PA
    The new style distributor ('95 up) is a great improvement over the ('92 to '94) old vented type. It will not retrofit to the earlier motors unless you change the timing cover, timing chain &amp; camshaft (or drill the front center &amp; install a longer dowel pin), to the 95' &amp; later stlye.

    As far as header clearance, there are a few engine brackets which can be used to relocate the engine side to side slightly. If I remember correctly, the 70's Camaro's offest the engine slightly to the pass side for clearance. These may help a little. Also be sure to get headers which are suited for angle plug heads (GM type angle is also different from race type Brodix &amp; Trick Flows etc.)

    The center ports are the same distance apart &amp; bolt pattern, but has a d-port shape...the round header will fit, but I suggest the special FelPro header gasket to help seal it properly.

    The LT1 had 275-285Hp depending on year (at approx 5500rpm)&amp; 325ft/lb torque (at approx 3400rpm). Will post exact data when I find it. Hope this helps.
    Lonnie
     
  13. 2Dogs

    2Dogs 1/2 ton status Premium Member

    Joined:
    May 4, 2001
    Posts:
    3,470
    Likes Received:
    35
    Location:
    Ca
    LOL. Last time I checked I think you had a monster mouse FI motor.... And you want an LT1??? I'll trade you for the one in my Vette.
    Talked to my engine builder - he has me convinced that we can build a better 383 FI or 350 with Whipple or B&amp;M that will have more low end torque. So I think I'll start counting my pennies for the Whipple.....

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  14. BurbinOR

    BurbinOR 3/4 ton status

    Joined:
    Feb 17, 2000
    Posts:
    5,829
    Likes Received:
    0
    Location:
    Oregon
    LOL............the LT1 would be for another project - heck if I had that motor I would find something cool to put it in..........maybe a 240Z............or a 2wd K5.............or..............

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com>www.blazzinor.rockcrawler.com</a>
     
  15. 88streetblaze

    88streetblaze 1/2 ton status

    Joined:
    Jun 27, 2001
    Posts:
    314
    Likes Received:
    0
    Location:
    middle of sticks, oklahoma
    ok, i found the article i was talking about. it was in one fo Street &amp; Performance's old catologs. if i read it correctly the lt-1 is 1/2 an inch shorter and 1/2 wider, not the inch i stated earlier. now the article was a little vague about whether it was the block that was different(which is what i assumed) or if it was combined with heads, but i think it is just the block because then they go on to say that the overall height was 3 inches shorter than the first tpi motors. and from the dealings i've had with these people i tend to belive they know their stuff.

    as for the dist. upgrades i mentioned before i should have been more specific, yes it is correct you can not actually replace the entrie dist. with a newer model, besides who would want to as expensive as they are. as already mentioned the gears are different in the back. but the only change that helped with longevity was the vacume(sp) line that runs to the dist.off of the intake. there should be a port on the intake you can use to add it, but you will need a new cap(which aren't cheap and you have to pull the water pump to get to the dist.) so that you will have a port to hook it to on the dist. and there is also another line that runs from the dist to the duct that attaches to the throttle body. With these pulling air through water dosn't get a chance to cause problems. And besides the different gears on back and the vac. ports i can think of no other signifcant differance between the two. you will need to buy the line off the dist from a gm parts dealer because it has a restriction in it.

    and as for other important things i ran into or other useless info there was a post several weeks ago about this.
    <a target="_blank" href=http://coloradok5.com/forums/showflat.php?Cat=&amp;Board=blazer4x4&amp;Number=268594&amp;page=&amp;view=&amp;sb=&amp;o=&amp;vc=1>http://coloradok5.com/forums/showflat.php?Cat=&amp;Board=blazer4x4&amp;Number=268594&amp;page=&amp;view=&amp;sb=&amp;o=&amp;vc=1</a>

    <font color=blue> If sancho knows what good for him, he best go run and hide. Cause daddy's got a new 45.</font color=blue>
     

Share This Page