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  #31 (permalink)  
Old 06-04-2015, 09:39 PM
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No way.....

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  #32 (permalink)  
Old 06-05-2015, 04:31 AM
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OP,
You need a pushrod length checker - don't guess at the pushrod length. I recently assembled an engine with .100" longer valves in new heads, milled deck .025". I did the math and came up with 7.9__ rod. I used Straub's midlift system to determine length and I needed 8.010. For the money you'll spend on a length checker will be saved later when you're reworking the heads because of loose guides and worn seats.

Also, do you really need to run this thing at 6500? I'd guess you're looking for all you can get as you have a solid cam. If that's the case, then using correct springs, locaters and pushrods is a must so as to preserve your budgeted dollars. If you don't have the budget to put in the life preserving parts, then keep your RPM's in the range to allow the engine to live until you can drum up the cash to get what you need.

Best of luck - Jim
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  #33 (permalink)  
Old 06-05-2015, 04:52 PM
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Quote:
Originally Posted by 64nailhead View Post
OP,
You need a pushrod length checker - don't guess at the pushrod length. I recently assembled an engine with .100" longer valves in new heads, milled deck .025". I did the math and came up with 7.9__ rod. I used Straub's midlift system to determine length and I needed 8.010. For the money you'll spend on a length checker will be saved later when you're reworking the heads because of loose guides and worn seats.

Also, do you really need to run this thing at 6500? I'd guess you're looking for all you can get as you have a solid cam. If that's the case, then using correct springs, locaters and pushrods is a must so as to preserve your budgeted dollars. If you don't have the budget to put in the life preserving parts, then keep your RPM's in the range to allow the engine to live until you can drum up the cash to get what you need.

Best of luck - Jim


Yeah you're right... I probably shouldn't spin it that high until I get some spring cups and figure out my pushrod length with the mid lift system.. not only that but I'm only running a cast steel crank with eagle SIR rods and Hyper Speed-Pros.. not exactly a strip machine. I may of gotten a little overzealous with that cam choice lol.


In different news, now that I have this new cam and single plane intake I CAN'T TUNE THIS TO SAVE MY LIFE!!!


I have a nice flat spot between about 2000 to 3000 when I stomp it from a stop, and I can't figure out if it needs a pump cam change or a stiffer secondary spring???


And it has a nice miss at part throttle cruise, and I'm down to a .028" IFR to try and clean it up (runs a little rich at part throttle) and it's still missing! The only thing I can think of doing next is going even smaller on IFR or trying a larger low speed air bleed???


Maybe I need to not try and build a race car, because apparently I suck at it lol.

Last edited by HeavyChevyDeluxe; 06-05-2015 at 04:57 PM.
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  #34 (permalink)  
Old 06-06-2015, 01:07 PM
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. Check for plug wires burning against a header for the miss... or a bad sparkplug...


. First guess for the bog is secondaries opening at too low an RPMs ...
.
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  #35 (permalink)  
Old 06-06-2015, 04:52 PM
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. Check for plug wires burning against a header for the miss... or a bad sparkplug...


. First guess for the bog is secondaries opening at too low an RPMs ...
.
Thanks Buzz.


I always forget to check for wires burning on headers. I did find one that was a little burnt but not bad. I went ahead and fixed it, but still had the low rpm miss.. So I went back up to a .030" IFR and changed out my low speed air bleeds to .070" and that helped, but may be a little fat for it because I only had to turn my mixture screws out about 1 turn from seated.


That didn't help much either, still missing low, so I finally gave in and hooked my vacuum advance canister back up (I didn't need it with my dual plane and my QFT metering block doesn't have a ported vacuum nipple, and I didn't want to run full manifold because my idle RPM was right where I wanted it).


I turned the adjuster in all the way so the vacuum can only advance a max of 10, which is good because I have a rapid mechanical curve of 19 initial and 35 total all in by 2500 RPM, so I can't have too much vacuum advance.


Anyway with the vacuum advance hooked up it runs about 22 initial, and it run so much cleaner at part throttle now. It doesn't smell as gassy and it seems to have a stronger note (still misses a little bit but hardly at all).


In terms of the vacuum secondary and flat spot, I haven't gotten around to testing it yet, but I went to the next stiffer spring size. I hope I don't need to run a purple or a plain spring.. because I'd never actually have the secondaries fully open, and with a 670 holley I feel like limiting the secondaries will really kill my top end.
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  #36 (permalink)  
Old 06-06-2015, 05:43 PM
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Let me throw this out there. In looking at the # 3 exhaust valve spring, you're awfully close to a coil bind type of situation at the upper/lower ends of the spring. A "partial coil bind" is going to impart more pressure/spring shock-harmonics to.......your push rods. Maybe try a set of 1.5 rocker arms, just to see what that leaves you with. Engine looks good, and thanks for your USMC service. junior stocker.
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