62 340HP carb
I have a friend who is building a 62 340HP and wants to know if anyone can tell me what jets and rods go into a stock carb at 1000ft altitude?
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Re: 62 340HP carb
One thousand foot altitude is not high enough to justify modifying the OE jetting. Maybe 3-4000 feet and above is worth the effort.
In general carbs of that era are set up on the rich side, and the most useful thing to do if you really like to tinker is to lean the cruise mixture while keeping the power mixture about the same.
This is easy to do with the AFB because swapping the primary metering rods is so simple IF you can find rods with a larger diameter economy step that have the same or nearly the same power step diameter..
Start with the next larger economy step diameter and go up progressively by the smallest increment until you notice some lean surge at cruise, then go back down one size.
The following threads are useful if you are looking for the optimum spark and fuel maps:
https://www.forums.ncrs.org/showthre...and-parts-list
If the dual point distributor still has the stiff OE springs that don't allow full centrifugal advance until 4600 RPM, there is a lot to be gained by installing lighter springs that bring in full centrifugal at 2500 to 3000.
If the engine is being rebuilt the weak first design connecting rods should be replaced with Eagle SIR 5700 or better aftermarket rods, and a LT-1 cam installed rather that the original Duntov cam. With properly setup OE equivalent valve springs incipient float is about 7250 and with massaged heads it should make close to 300 SAE corrected RWHP at 6500 with a usable power bandwidth to 7000.
The following thread link should be useful to anyone looking to rebuild a very reliable and optimized OE small block configuration that will look original and and pass a PV. The only real difference between the Special 300 HP configuration and any SHP/FI engine is use of the LT-1 camshaft to replace the original Duntov or 30-30 cams. The differences in inlet and exhaust systems are relatively minor players. (For L-79 use the L-46/82 camshaft advanced 4 degrees on 327s or if you want to convert a mechanical lifter SHP engine to a hydraulic lifter using the best OE hydraulic lifter SHP camshaft.)
https://www.forums.ncrs.org/showthre...tion-Documents
Scroll down the alphabetical order "keyword" index to the third listing under "engine rebuild".
Duke -
Re: 62 340HP carb
Thank you for your help. I .will pass this on. MarkComment
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