351w Build Help

robert fugate

Active Member
Oct 1, 2012
103
25
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valdosta ga
So i bought a 351w out of a 1997 e-250. Planning on rebuilding it with http://www.summitracing.com/parts/fem-mhp175-023/overview/
and possibly using http://www.summitracing.com/parts/tfs-5261t561-c03/overview/ for the heads. either the 56 or 66
http://www.summitracing.com/parts/tfs-51403005 for the cam. But i noticed the cam says 10:1 compression. And i cant seem to figure out the compression ratio on either head. Any help would be great.. Ohh and ill be running a pro comp victor jr style EFI intake with edelbrock elbow
 
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The kit you posted says its a 9:1 cr with a 63cc head so go with the 56cc head to bump it up a little. I also recommend getting a custom cam for it instead of the tfs cam. That cam has a ton of duration and somewhat lazy lobes. A custom doesn't cost much more(Fti charges 350$) and if you supply him with all your details the engine will make max power with better drivability. Are you going to keep this engine n/a or are you adding any forced induction down the road?
 
I also wouldn't use that kit. You're going to want a 1-piece rear main seal, and among other things, the gaskets that come in that kit are not ideal for what you're trying to do. I made the mistake of buying one of those kits the last time I went through my 302, and I ended up throwing away half of it.

Summit has a fairly comprehensive compression calculator. Just plug and chug:

http://www.summitracing.com/popup/calcsandtools/compression-calculator
 
I have a nitrous kit right now. But would like to turbo in the future. and was thinking when i was ready to do that i could just sell the 56cc heads and buy the 63cc to lower the compression. Nikwoac i havn't found another kit as complete or cheap.
 
I'm just going to say a few things and hope I don't offend you.
#1 that's a cheap kit for a reason. You get what you pay for.
#2 that kit isn't set up for any serious/or semi serious amount of hp(which a turbo is capable of)
#3 the cam is all wrong IMO especially if you're going with a turbo
Now here is my advise. Buy a quality kit at the start. You'll be way ahead in the long run. You won't have to worry about it going forward with a turbo etc and you'll make more dependable power. If you're really just trying to do it as cheap as possible and don't care if you break stuff because you're going to keep replacing it then go ahead. If you're going to keep it n/a and just want a street package that kit is ok but like Nik said I'd buy better gaskets etc. I don't know your level of experience with all of this that's why I'm saying some of this. Remember all the extras you're going to need with the swap and the supporting mods for the engine combination(fuel sys,ign,exh,tuning,etc)
I'd personally buy better pistons,rings,arp bolts and studs,gaskets,and match the cam with the turbo/head/piston combo
 
I have a nitrous kit right now. But would like to turbo in the future. and was thinking when i was ready to do that i could just sell the 56cc heads and buy the 63cc to lower the compression. Nikwoac i havn't found another kit as complete or cheap.

Unfortunately, there aren't a lot of all-in-one kits out there for what you're trying to do. The rear main, valve seals, intake, exhaust and fuel pump gaskets are automatically useless to you. I'm not sure if the timing cover/water pump stuff is right either, as they're for pre-74 blocks. The valve cover and oil pan gaskets are garbage, those multi-piece cork gaskets will leak from day one. I mean, you can certainly use them, but the new 1-piece silicone gaskets are leaps and bounds better. Take it from someone who bought one of those summit kits- there are better ways to go about this. It will just require a little more thinking.

Everything else in the kit is probably OK for what you're trying to do, unless you're looking for a lot of steam out of this motor. Talk to your machinist, but upgrading rod bolts and going to main studs are probably a good idea.
 
I have a nitrous kit right now. But would like to turbo in the future. and was thinking when i was ready to do that i could just sell the 56cc heads and buy the 63cc to lower the compression. Nikwoac i havn't found another kit as complete or cheap.
As far as selling and re buying heads, that is just crazy talk, you would be loosing a lot of money in a deal like that. Consider getting the 56cc heads not and running with a tad higher compression and then using a cometic head gasket to lower the compression to where you want it to be. I've used .120 cometics on motors before to do this and currently have .080 cometics on my 91 just to keep the compression down to a reasonable amount consider the amount of boost we are running with this motor.
 
I love the input. And get offended by nothing. I agree i really dont want to have to do this more then once. The car is prob gonna be 75% track 25% street. And have considered stroking it while i have all of this apart. I'm not looking to break any records but would still like to have somthing stupid fast. Turbo will be in the far future so i dont want a turbo cam as it could be many years before I'm ready for that. The cam i picked was because MMFF used it with those heads here http://www.musclemustangfastfords.com/tech/mmfp_1111_408_stroker_build_and_dyno_test_double_trouble/ Any kit help would be appreciated greatly. I am no mechanic though i read alot and watch alot of videos on how to and will be assembling this myself. And my budget atm is 3k for motor heads and cam :(
 
As far as selling and re buying heads, that is just crazy talk, you would be loosing a lot of money in a deal like that. Consider getting the 56cc heads not and running with a tad higher compression and then using a cometic head gasket to lower the compression to where you want it to be. I've used .120 cometics on motors before to do this and currently have .080 cometics on my 91 just to keep the compression down to a reasonable amount consider the amount of boost we are running with this motor.

Is there any concern about what that does to your quench? Just curious.
 
Not at all. I've seen motors melted down and in a rush situation the block and head will get decked on one side just for a quick turn around. there was one instance with a 521 BBF we ran a .051 cometic on one side and a .120 cometic on the other side of the motor to have equal compression both sides. 2 stages of nitrous and the et's and mph where identical before and after the rebuild. The only thing that I make sure of is that the cometic inside diamiter is the same as the bore diamiter not oversized like most typical head gaskets.
 
I love the input. And get offended by nothing. I agree i really dont want to have to do this more then once. The car is prob gonna be 75% track 25% street. And have considered stroking it while i have all of this apart. I'm not looking to break any records but would still like to have somthing stupid fast. Turbo will be in the far future so i dont want a turbo cam as it could be many years before I'm ready for that. The cam i picked was because MMFF used it with those heads here http://www.musclemustangfastfords.com/tech/mmfp_1111_408_stroker_build_and_dyno_test_double_trouble/ Any kit help would be appreciated greatly. I am no mechanic though i read alot and watch alot of videos on how to and will be assembling this myself. And my budget atm is 3k for motor heads and cam :(
Umm...not to pee on your parade but building an entire long block with those heads and a roller cam,timing chain,oil pan etc for 3k is impossible if you have to do some machine work. What type of budget do you have for the entire project? The reason I ask is have you priced all the little and major extras you will need? Do the cylinders need to be bored?crank turned?polish/balance,upgraded bolts and studs,diff distributor(assume this for a mustang)oil pan,headers,etcetc. Also for the induction side you have the intake,elbow,throttle body,fuel pump,fpr,injectors,and some type of tuning(the regular ecu isn't going to handle this without issues). Just an FYI
 
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In my prior experience take your budget that you figured on spending for the engine build and double it. This way all of the incidentals that @A5literMan mentioned above are covered. Doubling your initial figure may even be on the shy side of things. I speak the truth here and guess where that truth hurts? In the wallet lol
 
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In my prior experience take your budget that you figured on spending for the engine build and double it. This way all of the incidentals that @A5literMan mentioned above are covered. Doubling your initial figure may even be on the shy side of things. I speak the truth here and guess where that truth hurts? In the wallet lol

Haha yep. The peripherals will nickel and dime you to death. I’m pretty confident I have twice that budget in my current H/C/I setup, and I reused stock pistons.


In before someone says something about used parts and buddies who work at machine shops.