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.

How much HP gain from. . .

Discussion in 'The Garage' started by BowtieRed, Jul 30, 2004.

  1. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    OK, i got a GM Goodwrench 249/300tq engine. right now it's got headers.
    Next I just bought an Edelbrock Performer Manifold, how many horses do you think that'll give me?
    Next I'm gonna put a Comp Cams 268H Cam in it with a double roller timing chain
    Then a Edelbrock Performer Carb.
    Then roller rockers. What kinda power do you think i'll finally have out of it? It's going in a stock height (for now) 84-86 K10
     
  2. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

    Joined:
    Apr 20, 2004
    Posts:
    12,331
    Likes Received:
    1,039
    Location:
    Northern Colorado
    I just had my engine rebuilt, and I told the machine shop I was shooting for as close to 300hp as possible. I ended up with almost exactly the same combo. I do have Thorley headers. So you should be close to 300hp, at least 270-280hp IMHO.

    On a side note I would go with a Jet Performance Q-jet. Or the Edelbrock Q-jet, but they are a lot more money. If you do any wheelin at all, you'll be much happier. At the very least, get the off-road kit for the Edelbrock you're getting.
     
  3. CaveBlazin

    CaveBlazin 1/2 ton status Premium Member

    Joined:
    May 21, 2002
    Posts:
    1,348
    Likes Received:
    1
    Location:
    Middle TN
    Another thing you could do is buy a head porting kit for like $30. It would create some great HP gains.
     
  4. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    ok, that's cool, i was thinkin more around 325hp, maybe not though. ok, now what would ya'll suggest if i was looking for about 375-400 horses, maybe L98 heads with 2.02/1.60 valves and 10.5:1 pistons?
     
  5. backcountry

    backcountry 1/2 ton status

    Joined:
    May 27, 2004
    Posts:
    916
    Likes Received:
    0
    To answer the first part of your question. If I’m not mistaking, it states with headers and intake that those are the figures hp/torque you will get.

    I will run the numbers on my dyno software to answer your cam question. I shall respond shortly. /forums/images/graemlins/peace.gif
     
  6. backcountry

    backcountry 1/2 ton status

    Joined:
    May 27, 2004
    Posts:
    916
    Likes Received:
    0
    [ QUOTE ]
    To answer the first part of your question. If I’m not mistaking, it states with headers and intake that those are the figures hp/torque you will get.

    I will run the numbers on my dyno software to answer your cam question. I shall respond shortly. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Ok. Here are some numbers I ran for this part number. Comp Cam 12-242-2 (XE 268H)

    Hp would be about 357 and Torque would be about 382. If you let me know your valve sizes I can get even closer numbers. These numbers are with a 600cfm carb. headers and dual plain intake. If you add a MSD ignition, you can gain even more. /forums/images/graemlins/peace.gif
     
  7. backcountry

    backcountry 1/2 ton status

    Joined:
    May 27, 2004
    Posts:
    916
    Likes Received:
    0
    [ QUOTE ]
    ok, that's cool, i was thinkin more around 325hp, maybe not though. ok, now what would ya'll suggest if i was looking for about 375-400 horses, maybe L98 heads with 2.02/1.60 valves and 10.5:1 pistons?

    [/ QUOTE ]

    You can achieve those numbers if you have better head flows and no more than 10.1 on the compression. Even with 10.1 compression. I only use premium fuel. 10.5:1 is getting up there for pump gas. If you do it, make sure your timing is dead on.

    I would install an MSD Ignition as well. /forums/images/graemlins/peace.gif
     
  8. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

    Joined:
    Apr 20, 2004
    Posts:
    12,331
    Likes Received:
    1,039
    Location:
    Northern Colorado
    I just have the High Energy 268H cam, which is part number 12-210-2.
     
  9. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,095
    Likes Received:
    144
    Location:
    california
    I have the HE 268H cam, performer intake, hooker headers, performer Q-jet, 9.2 compression, ignition, in my 406 and I am right around 325-350HP. I would say 300HP with the goodwrench 350.
     
  10. backcountry

    backcountry 1/2 ton status

    Joined:
    May 27, 2004
    Posts:
    916
    Likes Received:
    0
    [ QUOTE ]
    I just have the High Energy 268H cam, which is part number 12-210-2.

    [/ QUOTE ]

    Ok. With that part number you will get about; 328 hp and 376 foot pounds of torque.
     
  11. POWERMAD

    POWERMAD 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    3,466
    Likes Received:
    0
    Location:
    Oregon
    I was diggin through an old Petersons camshaft and valvetrain rag and seen this write up on different cams.
    9.7:1 355
    AFR heads, 2.02/160: 190 runners.
    Ebrock Performer RPM intake

    Holly 750 dbl pumper
    Comp 268H cam
    Hooker 1 3/4" headers
    380hp @ 5,400/401 torque @ 4,100
    It made at least 400 ftlbs between 3700 - 4300 and over 350 ftlbs between 2700 - 5600.
    Over 350 horse from 4700 - 5800.
    It idled at 800 rpm with a slight lope and 16 inches of vacuum.
    Good write up. /forums/images/graemlins/thumb.gif they did Comps 252,268,280 and 292 grinds with the same plant to see what each one would do.
    The 268H cam was the best choice from that line up with that particular plant.
    It idled the best and had the flattest tourqe curve.
    The article stated that the 252 would have had better numbers had a performer intake, smaller carb and headers had been used.
    The 280 seemed to be matched but it had a choppy idle and a 2500 stall converter would be needed.
    The 292 would have done better with a single plane intake like the Victor JR and at least a 3000 stall converter would be needed.
    Everything was used out of box and all dyno runs were on 92 octane.
    They used a Comp timing belt and had tall Comp covers on it so I would assume it also had Comp roller rockers.
     

Share This Page