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boilermaster

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Everything posted by boilermaster

  1. All good points here fella's, I totally whiffed on the small driveshaft and rear yoke, that WOULD be a deal breaker for me. On the staggered shocks, there is info on the net to do a bolt on upper mount and different lower plate to convert to staggered shocks. I did this mod, very easy, just some square tube and flat stock, used one of the discarded lower plates for the top shock thru hole, Lets see what Ballaratcastle has for shocks, driveshaft and diff flange first. Boilermaster
  2. Ballaratcastle, your speedometer error signals that there is more than tire size at issue here. You had mentioned that you had recently replaced the rear shock absorbers, do you recall if your rear shocks were (staggered) Staggered rear shocks will have 1 shock forward and one aft of the rear axle. The reason that I ask is if you are going to use a LSD locking axle you are going to want staggered rear shocks to prevent wheel hop. The rear tires you currently have are still not going to help too much with traction if going to a locking differential, most will fit a 255/60R15 and still have traction issues. The speedometer error is easily dealt with by replacing the speedometer gear in the transmission, the accuracy will depend on BOTH axle ratio and tire size. As far as the axle ratio, the 351 Q equipped mustangs of the day that had the best suspension could be equipped with a 3.50 rear differential. I am not a convertible expert by any means, but something strikes me as odd about your sway bar attachment plates, why are they there ? weather or not you have staggered rear shocks will tell a lot, pretty sure that the rear sway bar only came with competition suspension. Perhaps a previous owner swapped the complete rear differential and not just the center section ? Boilermaster
  3. From water pump pulley to back of fan is about 1.75” A 2 5/8” spacer May put the clutch fan into the radiator. Klinton 994, a 7/8'' spacer will put your clutch fan in the same place as the standard flex fan that uses the 2-5/8'' spacer. I was NOT suggesting that you use a 2-5/8'' spacer, but trying to get you to compare the length of that 2-5/8'' spacer to the length of your fan clutch. Boilermaster
  4. Klinton 994, It looks like the standard fan spacer measures 2-5/8'' so measure from the water pump pulley to the fan and see if you are close to that measurement. If you come up short, pretty sure you can buy fan spacers of just about any thickness. or hope someone chimes in with an actual measurement from the front of the fan to radiator. I am running pretty much the same setup except 429 3 core radiator and have no issues. Boilermaster
  5. C9zx, True TDC is indeed in question here. My thinking is if I can get Big Red Mach 1 to advance his ignition until it spark knocks and then back off 2 degrees, it could raise his vacuum readings at idle and if his vacuum does indeed increase, that would be a half assed way of confirming that his cam timing is not retarded ? does that make sense to you chuck ? if Big red hit 15hg. valve timing should not be retarded. Boilermaster
  6. C9zx, The nice thing about comp cams is that they list lobe lift @ tdc , so no degree wheel needed if you actually know where true tdc is. Just look up your lobe profile in their master catalog and they give you the spec. from there you can do the math to figure out exactly where you are. I must admit that finding my lobes in the pdf catalog was a pain, but no degree wheel needed, just a dial indicator. So one can actually CHECK cam timing without removing the timing cover, unfortunately changing cam timing is a little more involved. Boilermaster
  7. Jpaz, Funny thing is that I decided to call comp's tech division where they ask for all of your engine specs and then select a bumpstick for you. Guess what they selected for me ? yup you got it. I did not take the bait and gave comp MY specs and had one built for me. This cam is not that far from the 270 but with split lift and duration and a lot less overlap and I make 17hg.@ warm idle. Boilermaster
  8. Good point Don c. on the crankcase vapors. Big Red, I would STILL like to see you bump the timing in 2 degree increments until you get just the hint of spark knock and then back off 2 degrees. That divot on # 1 piston is there for a reason, either valve timing or ignition timing. Boilermaster
  9. Big Red Mach 1, If you put a vacuum gauge in the cockpit and watched it you WILL understand. Hammer the go fast pedal to the floor and vacuum drops, as the engine accelerates and you gain speed you get some of that vacuum back, even at full throttle, that is how the secondary's open in the first place. Depending on the secondary's spring rating will determine at what rpm the secondary's open. Put in a really weak spring you will get a LEAN bog not a rich one. When the secondary's start to open they don't just slam open, they open gradually based on a vacuum signal. Start thinking of these power valves as a load switch and you may better understand them. That secondary power valves rating is only PART of the air fuel supply, you also have accelerator pump circuit, main jets, power valves and power valve restriction channel to consider here, and oh AIR, lots of air. If and or when you hook up wide band o2 and watch it in a high gear cruise, you will see it start out rich and get progressively leaner as rpm's increase, (because you are only using the main jets) as your rpm increases you are adding more and more air making it leaner and leaner. as this happens your vacuum becomes lower and lower, then viola, that power valve brings you back richer once again. Now gain some more vacuum and we start all over again with the secondary's. That rear power valve is based on a lot more than just it's vacuum threshold, consider jet size, secondary spring rate, venture size and throttle bore size. Boilermaster
  10. Hi Mike, Boilermaster here, Cooks, MI. Welcome to the 7173 Mustangs site. Ask any questions at any time here and you will the answers you are looking for and make friends.
  11. The current bracket that I am using, (believed to be 2v or a mutt) looks nothing like either of the pics that Don C. just posted. I think the issues lie in where the carb is being located on the throttle shaft or with the intake manifold attaching points. Boilermaster
  12. Ok Fellas, Your posts just got the best of me, so I went to my parts car, 73 q code 4 sp. car and pulled the bracket, as it looked completely different from the current bracket that I am currently using. First of all my current bracket (believed to be from a 302 2v) allows 100% opening from the loud pedal. I then removed it and used a square and marked where the attachment holes were in relationship to the cable attachment. Then I did the same to the Q bracket, same exact measurement, I would have sworn that the q bracket was longer and thus push the ball clip to a more forward position, this did not happen. With both brackets I am seeing the ball clip ahead of the ball stud by approx. 1/2'' (my Q bracket looks like the one Big Red Mach 1 posted a picture of) My little test this morning leads me to two possibilities : the ball studs are too far rearward on the carb lever or not all intake manifolds are of the same orientation (their bracket location to carb pad location may be different). Boilermaster
  13. Kevin, After what you have been thru, you deserve to do exactly what you WANT to do. That includes ANY modifications to what ever car you purchase, make it your own or you will never feel comfortable in it. Boilermaster
  14. Geoff, So two different engines with different displacements and compression ratio's They are what they are in their own respects, but shouldn't be compared. As for the .030 over 351's head swap, well As anyone knows our Cleveland's , the 2V and 4V used different camshafts and did not always share the same compression ratio's, so why no cam swap to compliment the increase in airflow ? What they did prove, total timing means something. I would have liked to see what they could have done with a 351 with appropriate compression ratio for 93 octane and a camshaft to match the 4V's airflow Geez, no carb tuning, shamefull. Boilermaster
  15. Big RED & Geoff. I figured that all of the shafts are and were always steel. There are bushings (plastic) both older and present carbs, but the older Holley's were Zinc . Now most all are aluminum and that will wear faster than zinc period... I am not an engineer but I can drive a train ! (sorry I just wanted to say that on the internet.) Yes I really can drive a train. Boilermaster
  16. Geoff, I don't specifically know that the actual throttle shafts are aluminum (hope not) but the carb body sure is, and I don't think there any bushings. Given that and where the pivot points are on the throttle shafts, all the pressure from the various springs is going to ride in a 90 degree arc to the rear of the throttle side and to the front of the non throttle side. Why prematurely wear this new carb out with too much spring tension. Boilermaster
  17. Ok Big RedMach 1, I see that in your picture of your carb install that you are running a throttle cable return spring. This is just an observation at this point but consider these facts. 71-73 mustangs throttle cable assembly's come with a return spring. Your carb has a built in return spring. If running an automatic transmission, your kickdown linkage has a return spring (only comes into play @ or near WOT. If you want to run an additional return spring, that's your call. This carb. you are installing is an ALL aluminum carb. I have not seen very many Holley carb's with worn out throttle shafts, but I have seen plenty of all aluminum carbs with warn out throttle shafts. If you choose to keep the return spring, I am suggesting that you at least take these steps (after start up) With engine off and all return springs disconnected (including throttle cable) see how freely the carb returns to closed, Then again with the throttle cable clipped on and lastly with the aftermarket return spring installed. If you feel that this is too much return pressure, you can always run a lighter return spring. Just my opinion Boilermaster
  18. Klinton994, try bumping to 16 degrees and see if that allows you to lower the idle speed, then if you can get it lower, recheck timing again at the lower rpm and try resetting timing. Even a stock distributor should show some mechanical advance at 1200 rpms. Boilermaster
  19. Klinton 994, Warm the engine up, lowest idle possible (vacuum advance disconnected) find the rpm where your advance quits advancing (hopefully 3000-3200 rpms and set the timing to 36 degrees btdc at that rpm. Do this with an assistant if possible so you don't have to hold the throttle and adjust timing at the same time. Did you have to advance or retard timing to get to 36 degrees btdc at max advance ? if you had to advance timing at max timing, you should now be able to lower your idle to a respectable spec. When you go to set your final curb idle you should be using the idle mixture screws to do that and NOT the idle stop screw. Tell us where your timing is at after doing this at lowest possible idle speed you should be 14-16 btdc @ less than 1000 rpms. Boilermaster
  20. Cv-72mustang, The hodrod article Did explain why the annular discharge boosters would like a larger main jet. If and when my s/a carb takes a crap, I would now really have to consider one of the summit carbs. Will be waiting on big red's seal of approval. Boilermaster
  21. So fella's, I went to summits website to check this carb out and read reviews. Two things caught my eye, primary and secondary power valve ratings. Summit has the primary power valve at a higher Hg. rating than the rear, this makes no sense. Then I read review # 28 and I believe the pv ratings are a typo. Second thing is primary jetting, the summit carb's primary is quite a bit fatter than what should have come in big reds avenger (this will not hurt big reds idle in any way what so ever. Both my 351 and 408 wanted the same primary jetting as what came in the avenger #72 and was confirmed by wideband o2 on both engines (not saying this is what big red needs or should have, just my observation). Way too many variables come into play here to even begin to make a suggestion . Boilermaster
  22. WOW, Tony-Muscle I would be all over this if it were not for the fresh unit I have in my 71 fb. Where were you in October when I was struggling to get mine rebuilt and I thought the post office had lost my rebuild ? LOL Boilermaster
  23. Don C, I am going to both agree and disagree with you on the idle mixture. If Big Red is at a point where his idle mixture screws have a zero response, then all bets are off because he can possibly be rich to a point where that mixture no longer supports combustion and that in turn would lower his vacuum reading. When I adjust mixture screws, I always find max vacuum and then start leaning from there, while watching the vacuum needle drop. So while your post is 100% true, it may not be in Big Reds case. if he has too much transfer slot exposed and a ruptured power valve and no response from the mix screws he could be to the point where is no longer supporting combustion. Boilermaster
  24. Big Red Mach 1, look at it this way, with that temp. and idle of yours, you are doing your part killing the virus. Your pcv valve WILL make a difference when you get the idle mix a little closer. I could send you a power valve blank (plug) for testing purpose, that way you could be sure what the pv is NOT doing. You could NOT drive it that way, as it would be way lean when a pv should open. Boilermaster
  25. Big red mach1 , I believe we have touched on this before, but what pcv valve do you have in Big Red ? just for the hell of it why not try adjusting the idle mixture with the pcv valve blocked off ? Would like to see what it does to vacuum reading and idle speed. After all the pcv IS a metered vacuum leak and you no longer have stock,, well anything. perhaps you have too high a pcv flow. Boilermaster
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