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I plan to rebuild a 351C this winter for my car. 2V open heads with port work. Its gonna be a pretty standard “street/occasional strip” build. I am doing this because I am uncertain of the strength of the engine as it is, and because I am starting to use oil.

I am going to zero the deck, mill the intake appropriately, and try to squeeze as much compression as I can with the opens and flat-tops without milling the heads except to get them flat if necessary. I am keeping my current cam, intake, carb, etc. I have some questions below that are designed to get me more information so I can give the machine shop more information so they can provide as good of a quote as possible.

Questions are:

Pistons. I am narrowed down to Speed-Pro forged pistons and Keith Black hypers. Other than the possibility of juicing the motor, is there any reason I would want forged pistons? The KB’s are ligther, cheaper, come in at .020 and up (help keep more meat on the walls), and (according to some) a better piston all around. Speed-Pro’s are forged, only .030 and .040 overbore, and (according to some) are subject to poor quality. I have no personal experience.

Oil Pump. I currently have a high volume on a standard pan. I am thinking I need to scrap the high volume for a standard, just because I don’t have the oil volume to support it. There is a high pressure spring kit made. Is that worth the time on a street/occasional strip motor? If it is, is it something that the machine shop should do?

Cost is a factor. The current timing chain, although 7 years old, doesn’t have many miles on it. Any problem reusing it?

Piston Rings. Is there anything wrong with getting pre-gapped rings? I am not a big fan of file-fit, only because I know how easy it is to mess up, and I don’t trust myself that much.

Should lifters be replaced? Keeping the same cam, and I am smart enough to keep them in order… I would think no problems on keeping them.

Line hone? The engine hasn’t spun a main or anything as far as I know. No reason to do a line hone then is there?

Engine balancing? That gets costly right? Is it worth the cost in engine longevity and performance? Something tells me no.

What kind of performance modifications can I ask the machine shop to do to my heads aside from porting? I don’t want to get radical, just some general stuff that they can make quick work of. I remember seeing someone write that they had a machinist that, while doing valve seats, opened up the area under the seat with his (insert name of tool here).

Guides. Any advantage to going ahead and just installing bronze guides regardless of the condition of cast guides that are there?

That about does it for the general stuff. Along the lines of “specific to this motor” questions, should I do anything with the rods other than new rod bolts? Something tells me that the moment I start modifying the rods, I am gonna probably need to get that balance job done.
 

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I only feel comfortable addressing some of your questions, but here goes:

a. Hypers are good pistons. I think forged are unecessary unless you are planning "unnatural aspiration" or heavy racing.

b. Std oil pumps are plenty adequate for mild performance builds.

c. Youd have to define "not many miles" before Id speak to your timing chain. My inclination is to replace it. I would almost always replace the timing chain and oil pump on any rebuild, but that just me. They are cheap relative to the cost of the rebuild in total.

d. I personally would balance the motor regardless; only for a strictly stock rebuild would I try to save a few farthings by skipping the balance job. It should not be expensive if you arent trying some exotic rod/piston/crank combination, and it will pay you back in higher-RPM longevity.
 

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I'll answer what I can and leave the rest to the REAL experts.

Pistons. I think the KB's are just fine for you and are of excellent quality. That's what I have in my 289, and is the standard piston for all performance engines built by the machine shop that I use unless someone specifically requests something different.

Oil Pump. Use a standard, stock pump. When discussing the upcomming 351w build for my sportsroof with the machine shop, Mike Parrish (owner), told me NOT to use a high volume or high pressure pump. "We are going to build your engine with very tight tolerances and a stock pump will work best. Anything else has a tendency to wash out bearings". The guy is an excellent engine builder, so I'll take his advice on that.

Timing chain. They don't wear out from age ... only mileage. Re-use the existing one.

Piston Rings. I'll leave this one for the experts

lifters: Unless there's some specific problem with your current lifters, just re-use them if you're going to re-use the cam. Word of caution, though. If you're going to have a machine shop rebuild the lower end, they will probably not want to use a used cam and warranty the engine. If you re-use the cam and lifters, it is CRITICAL that all lifters go back into the same bores they came out of.

Line hone? left for experts again.

Engine balancing: DEFINATELY. If the engine will ever see the track, balance it. Balancing only costs about $100-$150 and is money well spent. You will be AMAZED at how much metal they will remove. General rule of thumb ... if the engine will see over 5k RPMs, it needs to be balanced.

Heads: screw in studs and hardened valve seats if they don't currently have either.
 

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I'm going to have to agree with lman about the timming chain and oil pump. Balencing is good for higher rpm. I told my machinist about my stuff before i rebuilt my 302 and i used a new flexplate and and fluidapmer. and i quote"thats wont need balencing unless you go over the 275-300hp or 5000rpm mark"
 

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First I have to say I've never owned a Ford that didn't use oil. I don't know that I would base my rebuild decision on that alone.

Timing gear and chain: Prolly less than $20 for the set. Good insurance if you ask me.
 

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Questions are:

>Pistons. I am narrowed down to Speed-Pro forged pistons >and Keith Black hypers. Other than the possibility of >juicing the motor, is there any reason I would want forged >pistons? The KB’s are ligther, cheaper, come in at .020 >and up (help keep more meat on the walls), and (according >to some) a better piston all around. Speed-Pro’s are >forged, only .030 and .040 overbore, and (according to >some) are subject to poor quality. I have no personal >experience.

Go with the speed pro unless you want to gap your rings. KB require extra ring clearance unless the are gapped properly the expanion will bust the piston. Want to see one?


>Oil Pump. I currently have a high volume on a standard >pan. I am thinking I need to scrap the high volume for a >standard, just because I don’t have the oil volume to >support it. There is a high pressure spring kit made. Is >that worth the time on a street/occasional strip motor? If >it is, is it something that the machine shop should do?

uae a standard pump with a stock pan

>Cost is a factor. The current timing chain, although 7 >years old, doesn’t have many miles on it. Any problem >reusing it?

Inspect it for wear if it looks ok reuse it.

>Piston Rings. Is there anything wrong with getting pre->gapped rings? I am not a big fan of file-fit, only because >I know how easy it is to mess up, and I don’t trust myself >that much.

See comments on pistons

>Should lifters be replaced? Keeping the same cam, and I am >smart enough to keep them in order… I would think no >problems on keeping them.

As long as the lifters and cam don't show any abnormal wear reuse them. keep the lifters in order

>Line hone? The engine hasn’t spun a main or anything as >far as I know. No reason to do a line hone then is there?

Correct

>Engine balancing? That gets costly right? Is it worth the >cost in engine longevity and performance? Something tells >me no.

Most ford do not require any heavy metal so they are cheap to balance $150 around here

>What kind of performance modifications can I ask the >machine shop to do to my heads aside from porting? I don’t >want to get radical, just some general stuff that they can >make quick work of. I remember seeing someone write that >they had a machinist that, while doing valve seats, opened >up the area under the seat with his (insert name of tool >here).

If the were blending the bowls that is part of porting. Do not let them HOG out your heads that will hurt the flow instead of helping

>Guides. Any advantage to going ahead and just installing >bronze guides regardless of the condition of cast guides >that are there?

If the guides are good leave them alone.

>That about does it for the general stuff. Along the lines >of “specific to this motor” questions, should I do >anything with the rods other than new rod bolts? Something >tells me that the moment I start modifying the rods, I am >gonna probably need to get that balance job done.

Have the rods checked for size if they need sized have that done. Most places will not replace the bolt with out sizing the rod afterwards.

PM me if you need anything else
 

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I'll chime in...

Rings - I used the KB .020 hypereutectic pistons in my 351C rebuild, and the only thing I wish I would've done differently (in hindsight) was get the pistons that take the 5/64 rings, instead of the 1/16 rings. I was using Speed Pro moly file-to-fit rings, and broke one compression ring, and over-filed another. Had to buy another whole set of rings to replace them. 5/64 rings are easier to find (according to my machinist). Also, if you're going to use the KB hyp pistons and file-to-fit rings, read the filing instructions on both the ring kit, AND the pistons. The piston instructions said file an additional .010 off from what the ring kit says (total was .026 I believe).

And since you said that cost is a factor, here's something I learned from my rebuild: if you're going to re-use your water pump and the rebuild isn't going to take very long, keep the water pump submerged in water to keep the seal moist. You don't want it drying out. Ask me how I know.

BTW - had it balanced, and like Johnpro said, it cost me about $150.
 

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i have a question towards you... why not get a new cam and lifters, less then 200 bucks? if you get the right cam and stuff it will 'open' up your engine so it runs a little better then before, doing what you are doing is all good but the cam will make it more cost effective to do it all and in the process get a little more umph out of the engine then just a stock cam. im pressuming its a stock cam also i dont know other wise. the way i look at doing stuff, do the inside of the engine exactly like you want it the first time for 1) its a pita to pull the engine to replace things that you should have done when you built it in the first place. 2) save you money in the long run b/c you dont have to buy it twice. my .02
 

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Ive never done the line hone thing, and never ran a motor high enough I felt balancing was prudent.

What Ive read states bronze guides arent necessary, but knurled guides SUCK!!! (BTW.....Ive seen machinists put a SUPER SHALLOW knurl look in bronze guides...I suspect this was for oil to get in).


From what I can tell, the concensus on the 335 forum is that hi-vol pumps are a BAD idea for an engine with street clearances.


I run forged......I dont plan on turning 8500RPM, so their weight isnt an issue. The moly rings that came with my speed pro forged already had good gaps....if you might ever want N2O, ensure theyre a bit wider....


For rods, I used PAW's 200 dollar shotpeened, magnafluxed, mildon bolted stockers.


You may consider looking around the web for Cleveland pages that include an illustration of what Ford Motorsport recommended for Cleveland port enhancement......a lot of that could be done at home with a die grinder.........IMO, NEVER SHADETREE PORT THE FLOOR OF THE PORTS NEAR THE VALVES (the "short turn radius")!!!! any port work has to be done BEFORE the valve job!!!

(and obviously bigger isnt always better!!)



A $50 double roller chain is CHEAP insurance.....with an aftermarket cam, a chain break DEFINITELY would crash valves.

If you like your current cam (BM2?) I'd consider using it........along with a 2V Xcelerator.


Once a properly built engine has a good street cam, the ignition curve and the carb final tweaks make or break a motor's "satisfaction factor".


BTW.....what carb did you end up with?
 

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Speed-Pro’s are forged, only .030 and .040 overbore, and (according to some) are subject to poor quality.

TRW's used to be the standard by which all comers were compared. IIRC, Speed Pro took over the line (or numbers anyway) some years back. I built my most recent engine with old TRW parts so I can't speak to current Speed Pro quality but the TRW's have been bulletproof in all the engines I've built over the years. I never built one without forged pistons, either TRW, Venolia or Ross. Hypereutectics should be fine for your application, IMO.

I am thinking I need to scrap the high volume for a standard, just because I don’t have the oil volume to support it

That'll depend on the build state of the engine and the clearances the machine shop puts into it. Consult with them before making a decision. A larger volume pan would be nice if making more HP. Oil is coolant too, you know *G*

The current timing chain, although 7 years old, doesn’t have many miles on it. Any problem reusing it?

What kind of timing chain? Compared to the cost of an engine, a timing chain is snot rag stuff. If yours is OEM, get it outta there.

Is there anything wrong with getting pre-gapped rings? I am not a big fan of file-fit, only because I know how easy it is to mess up, and I don’t trust myself that much

Have the shop do it. They've likely got a ring filer. Don't skimp on piston rings, especially if making moderate or better cylinder pressures.

Should lifters be replaced? Keeping the same cam, and I am smart enough to keep them in order… I would think no problems on keeping them.

If everything looks good, re-using the cam/lifters shouldn't be a problem.

Line hone? The engine hasn’t spun a main or anything as far as I know. No reason to do a line hone then is there?

I would agree, if the bearings look evenly worn.

Engine balancing? That gets costly right? Is it worth the cost in engine longevity and performance?

Not that bad but it does cost. If you're running a different weight piston, you'll need it, or at the very least, if the new pistons are heavier, have them balanced to match the old.

What kind of performance modifications can I ask the machine shop to do to my heads aside from porting?

If not porting, just have them knock off any rough spots and clean up the bowl areas where the guide boss comes through and where the valve seats transition into the bowl. That's pretty easy to do with a die grinder.

Guides. Any advantage to going ahead and just installing bronze guides regardless of the condition of cast guides that are there?

If the cast guides are good, leave them alone. If they're OEM, they're likely not good. A bronze wall sleeve guide repair once was the ideal solution for racing engines but I don't know what's the hot ticket any more. I always made my own bronze guides for my engines.

should I do anything with the rods other than new rod bolts? Magnaflux them, first off. Then, get the big end re-sized after the new bolts are pressed in. The shop should automatically do this. IMO, the rods will be fine for your use without shot peening or flash removal.

Any other questions? *G*
 

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Everything pretty much covered, I'm using the KB pistons and really like them! If you don't plan in spinning the motor over 6300 RPM, I think they'll do fine!

The best rings (IMO) are the Speed-Pro plasma moly file-fit rings. Too many times I've seen "pre-gapped" rings with the gaps out of tolerance right out of the box. Other good file-fit rings are Hastings, Mahle...

I like to go with the factory tolerances on the main and rod bearings. Clevelands have a tough enough time with oil pressure to be "clearancing" parts for racing. .0015"

Buy the best rod bolts you can afford! Have the rod big ends reconditioned when the bolts are installed.
 
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