I'll be doing a tune up this weekend on my '49 GMC FC-152 with a '54 235 engine. I stoppd by NAPA this afternoon to get new ignition points and after doing the part # search on the computer the counter man asked me if it was a '54 truck or car engine... he had two different part #'s. I have no idea and don't know how to tell the difference between a 235 truck and car engine. My engine serial # is 0818638F54X. I got the points for the truck engine (NAPA Part # CS763A). Can anybody tell me how to tell the difference between the '54 235 truck and car engines. TIA for any help. Mike M '27 Chevy '41 John Deere B '49 GMC FC-150
That's interesting as my NAPA Echlin book only shows one set of points , there are two different cap & rotor sets but IIRC (prolly wrong) there was only one set of points for the early dists's . You should be able to match up the ones you need by looking in the Buyer's Guide as that has pictures . Be sure to buy TWO sets of points & condenser and toss the extras in the glovebox for roadside emergencies . -Nate
RE: '54 235 Truck or Car Engine (+ Nate - Thanks for responding. The NAPA part # on the points they sold me is CS763A. Does that match what your NAPA Echlin book shows? I've not put the new points in yet, but am puzzled about a reading I'm getting on my dwell meter with the existing points. Dwell meter shows 27º In one of your older posts you said you use a 30º target dwell for the .016 point gap spec. If memory serves correctly I should have to DECREASE my existing point gap to INCREASE the present reading of 27º to 30º. However, with the point breaker block riding on a high lobe on the distributor cam the point gap is too narrow to fit a .016" flat feeler guage in the gap. That can't be right... color me confused. Mike M '27 Chevy '41 John Deere B '49 GMC FC-150
RE: Setting Dwell & Points Gap You're right on target Mike , less gap = more dwell , the idea is to make the smallest gap that will allow long run time between tune ups as less gap means better coil saturation = MORE POWER but the points will wear & close up so there's a trade off . I know lotsa old hot rodders run like .010" points gap... Anyway , I'm off work for a week or two but I'll look up those points part # when I get back to it , here's hoping I can acess this page from work as they had it blocked for a while there . Remove the spark plugs and dist. rotor , push the dist. cap with wires attached out of the way and connect the dwell meter , crank the engine whilst watching the dwell meter and adjust the points untill it reads 30 ~ 33 degrees , stop , tighten up the points lock screw and re-test it to see if they creeped a bit as you tightened the screw . Re-assemble cap & rotor , re-install the spark plugs and fire it up , check and adjust the timing . If you cannot get the correct dwell without having absurd points gap , you have the wrong points . I hope this helps... -Nate
