How much HP??

Call me crazy but now it really sounds like it has one of those 2.5 power valves in it. PVCO's opening too late, besides other problems.

    79, its a new complete carbed engine with everything but the actual tranny. It is supposed to be run, set-up, tuned, timed, rocker arms aligned....EVERYTHING to just drop in and go!! The exact engine is the one in the SkiDim catalog, but was extra for the RH version. It has a electric fuel pump, appears to be the same as the EFI low pressure pump. Everything comes from the factory ready to go, therefore if I do too much playing with it (like taking the fresh paint off bolt heads) they might say it isnt covered since I touched it.
    I can say I have tried a new carb sent by SkiDim-still same trouble. To be more specific on what happens also, if I am doing 18 mph and give it a bit more throttle, nothing changes. Give it a bit more and the engine seems to die a bit, then go. It reminds me of a dead spot, but still puzzled because another carb didnt do anything.
                        Thanks again guys!

                             Jeff....

I think when you mash it, the accel pump is compensating for the a lean condition you feel when you go easy-up. The initial timing sounds like it can use a few degrees more advance to make the pop go away, but thats premature until we solve why its clanging at wot.

Final advance needs to be determined - should be around 36 degrees I suspect. If its less then that, then rotating the distributor is warranted. If 38 or over, then I think it could be contributing to the detonation.

I agree, you shouldn't have to go through this.

Ahhhhh Jeff, to much cold on your brain. Gotta go with Ford Blue.
But you are correct, ya can have trouble with either, Ford or GM, and when ya got trouble you'll do or spend about anything to fix it!

john

ReidP: Spoken like a true Ford lover, just like the jbear.

Yes, its sounding more like the secondaries are rich. But, that wouldn't cause noise.

Your clean insulator and sooty base suggests one throttle position is rich, then at some other position leans out and gets to temperature then self-cleans the insulator.

The secondaries will show their colors on the rear plugs before the fronts, there is just no reason for the mix to cross paths under the primary.

I've seen front plugs show lean because a PVC line was plumbed to an intake runner instead of the spacer or carb - that leaned just two cyllinders causing detonation, but lack of vacuum at WOT made the problem go away. But that doesn't sound like your 350's problem.

Is it a 4150 (two metering blocks) or 4160 (one metering block, one metering plate)?

Double-hmmm. My plugs are always uniform front-rear. There is something amiss with your carburation because the slant may affect the carb but not the ratios after it leaves the carb.

Sounds like a combination of problems. Not enough initial producing the pop/hesitaion down low. Rich condition on the rear, maybe a touch lean on the front but can't confirm till you cut the threads off a front plug after a WOT run.

A lean condition at WOT could be causing preignition on the front, producing the noise you hear.

Additionally, as the mix gets more dense at WOT, the flame front travels faster, requiring less advance; now too much initial can produce a knock, or If the span on the distributer advance is too wide. (chevys usually require less final advance than the typical ford windsor, because they breath better, producing a denser mix at WOT)

Is it a holley or quadrabog?

Run the engine solely on the primaries and see if it behaves. Then do a WOT plug check on just the primaries, see if the plug color now gets uniform front to rear, and measure the soot rings....if too narrow, you confirmed the primary circuit is too lean. Plugs should be white insulator with a 1.5-2mm ring at its base. Just because it may not knock doesn't mean the primaries are ok....check the plugs...the mix is not dense enough to produce the same condition on half a carb.

    ss201, thanks! That makes me feel a little safer. Exactly what I was after.

    79, Gottaski, I have a new damper plate that came with the bobtail. Its all new but the tranny itself. I tries the timing light, but noticed they are no markings on the cover like the rest of the engines. I have not played much with the newer engines, but I guess I will have to get a new light or some timing tape. The other issue is I cant realy touch too much on it as its under warranty, and dont want to take the paint off Any of the bolts as it could be used against me. I do know that the advance versus rpm seems correct visually with the light. They did send me another carb and still the same. I do know that changing the flame arrestor to the huge 454 one thats low profile made a difference and unplugging the PCV valve and capping it off made another difference where it runs much better. All parts are new, so seems like a possible valve misadjustment?? It should run 100% being a "drop in" ready to go, all set up and run new engine.
    I know the plugs when running WOT for a bit then shut down will result in black rear plugs and clean front plugs. Same as the OMC 225 due to the slant of the engine and more fuel going to the rear cylinders.
    Thanks Guys!!

                                  Jeff...

Thats weird. The trans can buzz, but clang/ping doesn't seem right, else it will frag shortly. 79 may be onto something.

What is the ignition advance at idle, 2000, 2500, 3000, 3500, 4000 rpm?

What do the plugs look like after a WOT run? Cut the threads off a plug, snap a pic of the soot ring, should be 1.5-2mm wide. Insulator should be white, not grey.

    Thats guys.. Thats great info!! Gottaski, the reason why I ask is because the 300hp new 350 PCM bobtail in the 76 will make this clinging/pinging sound at WOT, but cant confirm where the noise is cause it so dam loud. The tranny was original with 450 hrs behind a 302 and looked clean when I dumped the oil and poked around. Would there be anything in the 71c that would cause a noise like that?? All I have to do is back off the throttle a hair and it goes away. It seems when the 4 barrels are wide open is when it does it the worst. I have however had nothing but trouble so far with that engine and now the starter is dead after one season of 75 hrs. It hesitates sometimes real bad on LIGHT acceleration from take-off and will pop. Im still workin with Ski Dim to see whats going to happen. I took the oil pan off to move the drain plug and took out about 4 full tablespoons of liquid metal in the pan-before it even went in the boat! Sorry to get off the beaten path, but was wonderin if the noise could be the 71c.

                        Thanks!!   Jeff...

Hey Jeff,

You might have already seen this but according to the manual a 71C is rated for up to 255 hp, a 72C up to 380 hp. Seems a little low for the 71C, can probably handle more but don't know how much more.

Tim

    Hello to all, someone must know how much HP can you put into a 71c tranny and a 1" shaft?? They claim they are designed for small blocks, but what is the magic number on the maximum amount of HP in that combination before things go bad?? Thanks in advance for any replies.
                                    Jeff...