Topic: performance products for L79
in Forum: C3 Engines
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Hello Mr.Loghead68. Your car/engine should be a 327 350 horse with a .447/.447 gr.lift cam and with a great centerline.Do you have a spread bore carb( Q-Jet carb) intake manifold or a square bore(Holley,Edelbrock,Grant carbs)and is listed at 11.1 compression ratio according to the Vette book and my past experience.A reasonable upgrade without a lot of work would be to change the rockers.Attached is a set of roller rockers you might consider.I am not suggesting you buy these off of Ebay,however you can look through their system and see what is available.I would also suggest that if you peruse the internet,try and find sets that offer extruded aluminum as they are far more resilient than the cast aluminum. The 1.6 rockers increase the gross lift without changing cams.
Chevy SBC 350 1.6 Ratio 3/8" Aluminum Roller Rocker Arm Set w/ Posi Locks
Good luck.
Sal C nosal1
20152515373r.jpg)
11:1 compression is a pretty good start for some good HP. Check into having the cylinders and crank surfaces bored only if they need to cleaned up for the rebuild. Make sure whatever you do, DO NOT have the engine block decked if it is the original - that is machined where the block meets the heads. If the block is decked, the all important numbers found on the front right of the engine pad will probably be machined off and so will a good percentage of the car's value !! Double check with your machine shop, some will deck the block as part of their standard machining without asking your preference.
John Sigmund
valkman57@sbcglobal.net
NCRS Member 61302
NW NCRS Chapter Member
Duct tape is the new Black !!
Thank you for the information, I need all I can get. I have a q jet that needs rebuilt to put on it and I also have a spread bore Holley that I got for not too long ago. It's the 7885 model with vacuum secondaries. I liked the q jet better though, had better throttle response. And I'll ask the machine shop I have in mind if they do that. I wouldn't want the value of my engine to be gone. I know its pretty special.
Edit: and my father had told me the previous owner put a mild cam in it. I'm unsure of what kind or if anything else was done to it. I will know more when I start taring it apart.
|UPDATED|11/25/2015 4:34:56 PM (AZT)|/UPDATED|
|UPDATED|11/25/2015 4:34:56 PM (AZT)|/UPDATED|
Lifetime MemberSo Logan, what are your expectations from this engine?
GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.
3.54 Dana 44
'69 "N11" Sidepipes
Borgeson Steering Box
Born 8/1981
Sequence #3975
Click here to see more pics of my Vette on CarDomain.
Lifetime Member #26
Borgeson Steering Box
Born 8/1981
Sequence #3975
Click here to see more pics of my Vette on CarDomain.
Lifetime Member #26
I love the performance it already has, but I'm wanting a little more for now. I plan on swapping out for a more current engine in five or ten years. I'm not really sure what to expect out of it, it's the most powerful thing i've driven as of yet.
Loghead68 said: I love the performance it already has, but I'm wanting a little more for now. I plan on swapping out for a more current engine in five or ten years. I'm not really sure what to expect out of it, it's the most powerful thing i've driven as of yet.
Well, if you plan on swapping out the engine in a few years then I wouldn't sink a ton of money into it. I agree with Sal. A set of 1.6 roller rockers is a cheaper alternative to a cam swap and will gain you a few more ponies. Just make sure you will have enough clearance between the valve and piston with the additional lift.
I wouldn't up the compression. 11:1 is pretty stout. Maybe have the heads pocket ported and ports cleaned up and enlarge slightly should improve power a little.
I'm am (or was in the past) a fan of Rochester carbs. Holley carbs can be more temperamental from past experience. So I would have the Rochester thoroughly gone though. If there is slop in the primary throttle shaft that can be fixed with a bushing kit. Very common problem with Rochester's that causes a big vacuum leak there. There was a guy (Sean Murphy) Induction SMI that did a Rochester for me years ago. I was pleased with the results.
Or you could go with a 4 bbl EFI Throttle Body injection setup. That will retain that old school carb look with way more drivability/reliability. Which could be transferred over to your next engine swap if you decide to stick with a 4 bbl style intake.
|UPDATED|11/26/2015 6:33:56 AM (AZT)|/UPDATED|
GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.
3.54 Dana 44
'69 "N11" Sidepipes
Borgeson Steering Box
Born 8/1981
Sequence #3975
Click here to see more pics of my Vette on CarDomain.
Lifetime Member #26
Borgeson Steering Box
Born 8/1981
Sequence #3975
Click here to see more pics of my Vette on CarDomain.
Lifetime Member #26
Good Morning all and a HAPPY THANKSGIVING to all and especially for our troupes home and away along with all first responders everywhere.
I am in total agreement with Sarge on the Q-Jet compared to ANY Holley,however I hate Holley's for their inconsistency and constant leaks along with their fragile operation especially when the engine backfires and blows a power valve.
The 1.6 Roller rockers will increase the Gross lift to .477/.477 as to the OEM Cam of .447/.447 and should not be a problem,if you go this route.
I think I read they"changed to a milder cam",hence you should find out what the gross lift,duration @.050,valve lift, and center line is for the existing cam.
Good luck and happy motoring. Sal C nosal1
in Forum: C3 Engines
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