I am presently planning a rebuilt for my engine. It's my first rebuild. A 351m, still not sure if i'll go for a 400 crank swap. I want this engine to be street driveable, good torque, reliable. The engine will be .030 over, stock rod.

What is the maximun compression ratio if I want to run on regular (lower octane) pump gaz? Also what is the safe spot if I don't whant any trouble with pigning?
Still trying to figure out how to rebuild than thing, what to mill and what to leave like it is. Usually do you guys deck the block and the head? How much? .010, .020??

Can you guys give me some advice on that rebuild.

Thank
Redj

 

It depends some on which engine you build. The 400 is the most bang for the buck. Also the altitude you live at is a factor. For most people 9 to 1 is about right for mild builds but will require premium most likely.

 

Thank
I live at 1150 foot above sea level in Canada.

Where is the best spot to stay in the 87 octane fuel?

 

The stock CR for a 351M and many other Ford engines built after 1974 is about 8.0:1. If you use a stock cam, you can expect to use higher octane fuel if you increase the CR much above 8.0:1.

You should not deck the block or mill the head unless they need it. Be aware that many replacement pistons come with a lower Compression Height than stock, and will produce lower than stock CR unless some milling or decking is done.

I would recommend building it as a stock 400. If you use flattop pistons you may need high octane fuel, but stock dish pistons will produce a CR of 8.4:1. I believe that these motors ran on 87 Octane fuel.

You should also use a cam like a Comp Cams 255DEH to maximize the power.

 

Thank Danlee, your advice are really appreciated from a first time engine builder. I would like to ask you or other what you think about that.

The cam you suggested 255DEH, is what I think is right for my application. I was also considering the 260HR. If I can I would like to have hydrolic roller rocker. Would it be good for my application or a little overkill? Is it a wise investment or should I spend my money on other thing?

For my 400 build I am considering using these parts.

carb = edelbrock #1400
intake = edelbrock performer 400 EGR #3771
cam = comp cam 255DEH or 260HR
rocker = comp cam rocker or scorpion roller rocker
valve = stainless steel (still have to find some, need help)
porting = I am planning on doing some on my own
piston = 400 piston (still have to find some, need help)
header = hedman header elite series #89368 1 5/8" 3"
ignition = MSD 6A

What you think about that? I need help on choosing piston, any suggestion?
Keep in mind that I whant to run on 87 octane fuel.

Thank

 

Have you already disassembled the engine? If not you may want to check your deck height once the heads are off. I used the Badger flat tops without decking the block and they ended up between .065-.070 down the bore which TMeyer told me is about normal. When I did my head work I slightly unshrouded the exhaust valves and had a chamber of 82.3cc. This ended up giving me an 8.7:1cr. I am running the 941 Crane powermax and am right at the bottom of their recommendation for cr for that cam. I have no problem at all with 87 octane and 14 degrees initial timing. My mistake was taking too much off the head chamber thus lowering my cr farther than I wanted. Live and learn. If you go +.030 and get your heads to 79cc at .065 in the hole it would give you a 8.95:1cr. Depending when your exhaust valves close with the cam you use would alter your dynamic cr and possibly make it do able on 87 octane. I also have the Scorpions and like them.

 

For my 400 build I am considering using these parts.

carb = Edelbrock #1400
intake = edelbrock performer 400 EGR #3771
That is the EGR manifold and carb. I would suggest the 1406 non-EGR carb, unless you have to meet some smog police requirements. The #3771 manifold is OK, you can block the EGR off, if necessary. The difference between the #1400 carb and #1406 carb is the metering rods. You could hook up the EGR and use the EGR metering rods to get past the smog test, then block off the EGR and swap in the non-egr metering rods.

cam = comp cam 255DEH or 260HR
I prefer a hydraulic roller cam. The 260 HR is good, but these motors like dual pattern cams like the 255DEH. Call Comp Cams and ask for a dual pattern Hydraulic Roller.

rocker = comp cam rocker or scorpion roller rocker

With a roller cam you will need an adjustable rocker, as well as new pushrods and guideplates.

valve = stainless steel (still have to find some, need help)
Try Summitracing.com. Mine are Manley, but any decent SS valve will be OK.

porting = I am planning on doing some on my own.
Pay close attention to the exhaust ports.

piston = 400 piston (still have to find some, need help).

Tim Myers piston is of no help to you, because you have open chamber heads. I would recommend a Badger flattop, but your CR will be close to 9.0:1 before any decking or milling. The Dynamic CR with a 255DEH or similar cam will be about 7.8:1. That DCR is in the range for High Octane fuel, maybe 89 Octane. A stock replacement piston will give you about 8.3:CR with no milling or decking. The DCR with a 255DEH cam will be 7.2:1. That should be OK on 87 Octane, but I have no information to say for sure. 93 Octane fuel only costs $0.15 per gallon more than 87 octane at some stations. You will spend more than $2000.00 for this rebuild. At 10 MPG you will drive 133,000 miles before you spend an extra $2000.00 for fuel.

header = hedman header elite series #89368 1 5/8" 3"

ignition = MSD 6A
The Duraspark II ignition is just as good.

 

Thank a lot Danlee, your advice really help me. I might go on higher compression, it seem to be the way to go. Let me ask which valve is good for my application from manley. Race master or severe duty an witch part no. I don't know which diameter to look for.

Also I don't need the egr on the intake. I have some concern about the non-erg version being very thin at the base of the carb. I'll go with the 1406 carb and probably the non-egr version of the intake. I have sent a email to comp cam regarding a custom grind cam like the 255DEH in roller version.

I also read the post from 278broncos

https://www.ford-trucks.com/forums/s...d.php?t=288164

he build something very close of what I am looking for so I'll keep is post for reference. Concerning is custom grind cam, would it be better for me to be less agressive, something closer to the 255DEH pattern???? I am asking because people seem to be unsure about premature wear and reliability.

Any opinion on this one

If you yould like to see my restoration project, see it in picture at

http://photobucket.com/albums/v390/redj/

Still lot to do.

 

I think that the build of 278broncos was good and well thought out. He seems quite happy with the results.
The EGR Edelbrock manifold is thin at the carb base. There have been people who had trouble with those. The non-EGR manifold is better, but look at the Weiand 8010. I think that it is better yet.
Hydraulic Roller cams wear less than flat tappet cams, and last longer. Just let Comp Cams know that you are interested in reliability, and they will make sure that the ramp rates are not too agressive. The cam 278broncos used looks like a good choice, but I don't know what the ramp rates are. Comp cams will probably recommend a similar grind for you, since your aims are similar to his.

I would let the machine shop select the valves to use, since there are a lot of details involved in selecting a valve. The machinist will figure out the valves and springs, based on the cam manufacturers recommendation and his measurements.

 

This is what comp cam suggest me for a custom grind roller cam.
"Redj,
The cam I would suggest is a custom grind. The part number is 32-000-8RF. The grind number FC 3311F/3312F HR 110+4. The specs for this cam are 206/212, duration at .050". The lift is .553/.562 with a 1.73 ratio rocker arm. The lobe separation is 110, with 4 degrees advance ground into the cam.
Thank you, "

What you think about that????

 

The 4 degrees advance will greatly increase the low end torque, be sure you do not raise the CR at all with this cam or you will have problems with regular gas. It also has plenty of lift to take maximum advantage of head flow.