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Post Info TOPIC: Broken rocker arm in 68 396 Grande Parisienne


A Poncho Legend!

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RE: Broken rocker arm in 68 396 Grande Parisienne


Earl36 wrote:

Yes, most likely replacing the whole lot of them is not a bad idea. Any suggestions on type of make to use? Any preference or any types to avoid?


         good time for a lumpy cam and new timing chain   nice headers and Flowmasters    maybe a bigger carb?   



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1988 Chevrolet Suburban 9 pass 350 4 speed "survivor"  



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427Carl wrote:

  good time for a lumpy cam and new timing chain   nice headers and Flowmasters    maybe a bigger carb?  

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427Carl, you see right through me!  I was also thinking perhaps this might be a good time as well to take this engine closer to the L34 350 hp version.  I am a bit budget sensitive at the moment so currently I have only 1 NOS GM rocker, ball, nut and push rod on the way.  I was thinking that I would install the new parts, run the engine up and see how the repair goes and see what the engine sounds like running on 8 cylinders once again.  Then, I was thinking that I would compression test the engine and see what the results are and go from there.

But, if the compression test looks good and if the engine sounds and runs "normal", then perhaps a bit more cam might be in the forecast.  The L34 396 used the same heads as my L35 396, but I believe the L34 used a slightly higher fuel pump pressure, a Holley carb, had a forged crank vs the nodular crank on the L35 and of course the L34 had a higher lift cam and slightly higher spring pressures. 

Cam specs on L35 and L34:

Intake lift: L35 listed as 0.3983 lift at 0 lash, L34 listed as 0.4614 lift @ 0 lash.

Exhaust lift: L35 listed as 0.3983 lift at 0 lash, L34 listed as 0.4800 lift @ 0 lash.

Duration: L35 intake and exhaust duration listed as 286 degrees, L34 intake and exhaust listed as 300 degrees.

Overlap: L35 listed as 59 deg, L34 as 72 deg.

So, the question is, if one did up the cam a bit more bearing in mind the heads remain the same, crank stays the same, maybe gets a new fuel pump and maybe a different carb, new valve springs of course and push rods, what cam would you use?  Should one try to fall in around the L34 cam specs or bit higher lift up to .500 with these heads?

427Carl tossed it out there, any suggestions??

Jake

 



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Earl36


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I've used the stock GM 350 horse 396 cam in both 396 and 427. I love that cam. I think it's perfect. If you do replace the cam, make sure you don't make the common mistake of overcamming, especially in a big heavy car like your's that also likely has 2.73 gears.

And personally, I love Quadrajets, I wouldn't change it.

I lean very heavily to the original side. Headers are for race cars!

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1966 Strato Chief 2 door sedan 283 "survivor"


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How did you make out with this? I keep seeing your car at the top of the page and I hope you have it all back together by now.

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1966 Strato Chief 2 door sedan 283 "survivor"
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