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Discussion Starter #1
I am trying to sort out my 64 Galaxie with a 351C drag racing motor, toploader and now 4.11 gears.
This is actually a 400 block with 351C 4V heads, Torker intake, Holley 750, solid roller cam, Jomar stud girdle and Eagle rods.


It was definitely built to rev, but I can't get more than 5000 rpm's out of it and it is rather slow getting there.


The engine had been crated for 15-20 years and the rockers were not loosened. The motor also just has stock exhaust manifolds and a 2 inch full exhaust.


I am trying to figure out if it is:


weak valve springs from the storage
corked up exhaust
ignition- it has a Mallory Unilite, rotor looks good, unknown coil. Putting a new MSD Blaster II on tomorrow.


Someone rode with me and said it is not the carb, he could smell it, said if it was the springs, it would be skipping at all rpm ranges. Said put the coil in and a MSD 6AL.


Any help in determining what could be causing this problem would be appreciated.
 

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Valve springs very possible, also could be ignition components could be responsible for rpm miss along with valves sticking open.
Exhaust manifolds could be causing low rpm sluggishness along with cam or timing.

An engine setting for all that time I would have gone through it and done a refresh on it.
 

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It’s ignition I bet. Check coil, but first check the easy/cheap stuff first. Cap, rotor, wires, plugs, the coil. Sounds like you are arching over to other plugs at high rpm. But only a guess. You need to test stuff first. Easy problem if you are methodical.
 

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Lot's of stuff here and the exhaust is SURE not helping, likely to the tune of 50 hp if that is a rowdy engine

Here is how I would attack

1 - Check timing and timing curve. Look for two things, A - What the curve is from idle to when it stops coming in. B - Does the timing mark jump around ever? A will tell you if the timing is late, B will tell you if you have an ignition problem

Some additional things, with the Unilite, make sure that after running for a while, you check voltage AT THE POSITIVE SIDE OF THE COIL, yelling because people want to check the red wire to the module, that side of the module can handle 14+ volts. However, as the field collapses in the coil, "coil fires" , anything over about 11.5 volts will backfeed the Unilite and it will start to fail. Generally, the stock Ford resistor wire is not sufficient. Don't worry about resisting the coil too much, a change in voltage to a coil input has very minor changes to the output. If you decide the Unilite is failing, there are significantly cheaper alternatives with Accel or Mallory points elimination kits, same module but 1/2 price, then you can either fix the feed voltage, or add an MSD box to get to a low voltage trigger

2 - If timing and ignition is behaving check for WOT without trying to hard with someone pushing on the pedal, not with you working the throttle under hood. (engine off) Often floorboard design, angle, etc, will keep from complete full throttle. Once there, you work the secondaries and see if they are binding on a gasket or not opening for some reason. An example, I put a customers Chevy on a local chassis dyno and we went from about 400 RWHP to 500 RWHP with nothing but a timing change and getting full throttle

3 - Depending on the profile of the cam, and VERY likely, you have some dead valve springs. Might be a good time to borrow or buy an on-the-car valve spring pressure tester. At the same time, measure valve lift so you can see what open and closed are. Valve springs don't last forever and the amount of time, even if they were brand new, could have some tired ones. Also, your guy is incorrect, although a broken valve spring will skip, a soft one starts losing control and is seen as a jagged HP curve. They don't dead skip, and in fact, I have seen old springs act like a rev limiter in some milder applications. That alone could be your issue

4 - After checking the other things, be sure the valves are lashed correctly. It will change behavior and too tight is far easier on parts than too loose (within reason, the valves have to close)

5 - Finally, a high-winding 400 will never really make power with that exhaust. It shouldn't really break up, but it sure will lose a lot of power.
 

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Geeze... No matter what, that engine will NOT produce power above 5k rpm wheezing through exhaust manifolds and 2" pipe!

You're trying to ventilate 400ci. That exhaust would have a hard time making any power on a 302. You need to do a MASSIVE exhaust upgrade! Ideally, I'd like to see headers, 3" pipe, and some see through mufflers, like Dynomax Ultraflos! Get as close as you can to that.

Of course, checking everything Ross (My427Stang) said can't hurt, but it won't make any kind of power with the existing exhaust.

Good Luck
 

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Discussion Starter #6
Thanks for all the great input!
I will try to be methodical with this.
I did install a new Blaster II coil with its new ballast resistor. I found the old coil to be mis wired with the red dist. wire going directly to the coil + instead of the ignition side of the ballast resistor resistor wire.
I this and it now runs smoother and stronger, but it still won't do much past 5000 rpms. The wires and plugs are new and the rotor and cap look good, but I will double check.


I will check the timing, advance and throttle today.


The exhaust is the most challenging, as nobody makes headers that fit this combo. The mechanic who knows the history of the engine said at one time this car had headers on it that were for a 70 Torino. The only ones that fit that that could be close are a few Hooker headers Super Comp 6210 and Dougs D670S2. Both co's. wont say they will fit though. Expensive guinea pigs.


FPA and sanderson both say no go.


There is a header fabricator 30 miles from here that I may check with $$$.


Any ideas on this header situation? Would just going to 2 1/2 exhaust with good mufflers make much of a difference in the meantime?


Is it possible to pick the proper replacement valve springs if I don't know the specs of this stout solid roller cam, like pulling ID #'s off of the springs or the paint marks on them?


Thanks!
 

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Discussion Starter #7
Oops. 2 1/2 or 3 inch exhaust. Would either of those help much on its own for now?


Also, a guy on a 351 C forum suggested that the wire from the 50 year old ignition switch may not be providing a full 12 volts to the coil. Could this be a likely problem? He said maybe bypass it directly to the battery with a relay to make sure 12 volts is delivered.


Would a MSD 6AL also help this engine much with performance?
Thanks,
 

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Oops. 2 1/2 or 3 inch exhaust. Would either of those help much on its own for now?


Also, a guy on a 351 C forum suggested that the wire from the 50 year old ignition switch may not be providing a full 12 volts to the coil. Could this be a likely problem? He said maybe bypass it directly to the battery with a relay to make sure 12 volts is delivered.


Would a MSD 6AL also help this engine much with performance?
Thanks,
As for increasing pipe size, it will definitely help. Some of those 351C exhaust manifolds aren't that bad. Way better than what comes on an Windsor! lol As for mufflers, units like the Walker Dynomax are 'see through' cost zero horsepower, yet are still very effective. They work through sound ABSORPTION. The longer they are, the quieter. With a larger car, there is usually enough room for the longer mufflers, and you'd be surprised at just how quiet they can be.

As for pipe size, if you're using manifolds, you're probably limited to whatever size fits the manifolds. Of course, you could always 'up' the size using an adapter. 2.5" is what would probably work the best. Are you using tail pipes? If so, research what MANDREL BENT tails will fit your car. Flowmaster makes tails for less than a shop will probably crush bend a set for. With all the bends of a tail pipe, you're ahead to go this route.

BTW, what kind of car is it?

MSD boxes are nice, but in my opinion, you won't have a decent baseline until you get the exhaust freed up... as you will NOT do the engine justice until it can breath...

Good Luck!
 

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I searched a bit, and found this on the fordfe.com forum.

https://www.fordfe.com/anyone-know-where-to-find-prebent-dual-exhaust-ove-t107675.html#p996741

my '66 Gal I took a chance and ordered the Flowmaster 2.5" units for an A-body GM, reasoning that both vehicles were coil spring suspended in the rear. They worked beautifully - I even utilized my OE hangers. I did have to add a short extension/turnout to the back to accommodate the longer rear deck of the Gal (they may be even more adaptable to your Torino). Here's a Summit link - looks like they've gotten quite a bit pricier: http://www.summitracing.com/parts/flo-1 ... refilter=1
Randy Millard (Henrysnephew)

Summit Link for 2.5" Mandrel Bent Flowmaster Tailpipes! HIGHLY recommend the 2.5" Mandrel Bent Tails! Only $148 for BOTH SIDES!
https://www.summitracing.com/parts/flo-15802/applications/year/1968/make/pontiac/model/gto?prefilter=1
 

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As far as the valve springs, all you need to do is measure lift, preferably on the rocker side and easier that way, but be sure you have lash set to where you want it and you are careful. Once you have open and closed spring heights, many of us can get can get you pretty close, although I don't really fancy myself a solid roller guy, I'd probably lean on a buddy.
 

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I'm trying to figure out what the engine actually is.
It's a 351C drag motor, but it's a 400 block with 351C 4V heads? To me that sounds like it's a 351M with 4V heads, as the 351C crank won't fit a 400 block because the journal sizes are smaller.
 

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Discussion Starter #12
The car is a 64 Galaxie 500 fastback. Yes, the Flowmaster systems are nice. Used them on my Firebirds.
My Glaxie has leaf springs, so I probably can't use the GM A body kit. I will check to see if they have anything else that would fit. Will definitely use the longest see through mufflers I can fit on it.


The engine was built by a drag racer in GA quite a few years ago, and was bought from his estate. It is definitely a 400 block with 351C 4V CC heads, solid roller cam, stud girdles, deburred block, Torker intake. The guy that bought and stored the engine for several years actually pulled the pan to verify that the engine had the good parts that the racer's son said it did.


I don't know what crank is in it. It sounds like it would have been a good idea to get the extra cubes from the 400. I don't see why a drag racer would build a 351M vs. 400.


I did get a chance to check the throttle linkage today, and it is right. So, on to the trickier stuff for me to check.


Thanks.
 

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Discussion Starter #13
427stang, can I measure the lift without having to loosen or remove the rocker? The lash is set correctly now, and replacing springs and lashing a solid, especially with a stud girdle, is above my pay grade.
If I can get the right springs, I can find somebody to install and set it up.
 

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I'm trying to figure out what the engine actually is.
It's a 351C drag motor, but it's a 400 block with 351C 4V heads? To me that sounds like it's a 351M with 4V heads, as the 351C crank won't fit a 400 block because the journal sizes are smaller.
The 351C and 400 do not share the same crank. You can actually convert a 351M to a 400 by using the 400 crank and pistons. They even share the same rods. The blocks are functionally identical. A 351C piston can be used, but the rod has to be bushed down to take the smaller 351C pin. TMeyer is a company that specializes in the 351C/351M/400 engines. https://www.tmeyerinc.com/

As for the intake, the only single plane I can recall for the 351M/400 is the Edelbrock StreetMaster. No Edelbrock Torker that I can recall.

A picture of the engine, especially the front, would be VERY helpful. A picture of the intake as well. It might just be a 351C.
 

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Discussion Starter #17
Yes, calming the engine down with a milder cam would be an option, but I would really like to see what this combination is capable of, especially if I can get some headers on it.


The engine is definitely not a 351C, as it has a 1 inch ridge next to the distributor running front to back, which the 351C does not have.


There are intake spacers on the heads allowing the Torker to be used on this wider, taller block.


I haven't had a chance yet to check the ignition further, but will do so. Hopefully, that is the issue.
 

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Okay, if I'm looking at it right, it appears that they used adapter plates to mount a 351C intake on the 400 block.

As far as swapping in an milder camshaft... That all depends upon compression. A longer duration cam closes the intake valve later in the compression stroke, trapping less air. This is why engines with bigger cams need more compression ratio. If this engine is already high compression, installing a mild cam will build too much compression, and either require race gas, or simply not work. You could use a compression tester on the engine with it all warmed up, and see what kind of numbers you get the way it is. Pump gas will be limited to around 185 psi, and going to a smaller cam will increase that number significantly.
 
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