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Discussion Starter #1
Well, the 302 just blew in my '70 mustang while the 351w was in the machine shop, so this build was meant to be.

I have a 1969 351w (9.480 deck height) and had a heck of a time finding a kit that would work, and I think I managed to find one:

12360-PS-F408W - Ford 408W Reverse Dome -22.0cc Pro Street Engine Kit
(Site for the kit for those interested)

Spec's for bottom end-
Reverse dome piston: -22
Piston compression height: 1.280
Rod length: 6.200
Stroke: 4.000

Ran the math and figured this would be my best bet for the bottom end, came to 9.480 (Unless I got the math wrong, correct me if I did!) Want to make sure the pistons wont be sticking out of the block forcing me to run a thicker headgasket (would like to keep from having to run a 70mm or more gasket if its sticking out more than 0.020).

Last thing; this kit says with a 58 combustion chamber head, compression would be 10.36:1, and with a 72cc head, compression would be low 9s (assuming 9.1:1 or around there). Plan on running up to a 250 shot of nitrous, would the higher compression be better? Thank's, any info is appreciated, waiting till I can put the motor in the 'stang!
 

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The kit looks like it would be fine but the question remains "what is your goal" just high hp, cruise, race street strip? Only advice I can offer is this, decide on your target and build that engine.
 

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Definitely don't run a 'thick' headgasket to reduce compression. Usually, instead of reducing detonation, it makes it worse, because you end up with an 'open' chamber instead of having good quench. Plus, thick headgaskets tend to leak more easily.

Same problem for dished and reverse dome pistons. They are frequently very octane-sensitive. If you have a choice, run flattops. If you get some good aluminum heads, you can usually run a full point more compression than would be reasonable for cast iron, so that will help. Running a cam with lots of overlap may or may not be what you had in mind, but that will also 'let out' some of your compression at lower RPMs and help with detonation. Plus an old-school snotty idle is always cool. =)

I wouldn't be afraid of 10.5:1 compression with even a mild cam, like the HO grinds, with aluminum heads. If you can get away with it, a mild cam would make for a really vicious street driven car. The 408 is a wicked torque monster anyway, and probably will not have any trouble melting your tires down to the cords regardless of rear gear ratios.

If you plan to run nitrous, make SURE you let your builder know. Ring gaps are critical. Most guys that just throw on a nitrous kit will blow their engines because the rings heat up, ends butt together as they expand, and then it jams in the bore. When that happens, you break your ring lands out, lose a piston, and window the block.

That said, most stuff you do to make a N/A motor happy will also make a nitrous motor happy. Making sure you are not octane-sensitive will *really* help, because if your nitrous tune isn't perfect for every cylinder, it'll be more forgiving.
 

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Discussion Starter #4
Silver69, basically the car is now just a weekend fun car, but still be able to daily if my backup needs repairs. Not looking for a full-on drag setup, however would like the end goal of street warrior; hopefully it all goes well lol.
 

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Discussion Starter #5
Grimbrand, don't worry hah I don't plan on reducing CR with a thicker gasket, the thick gasket would only need to be used if the pistons stick out the hole too much ('69-'70 351w have the shorter deck of 9.480 compared to the later based 9.5 deck of '71 and later 351w, making it important to know what the specs of the kit are, having to shave the pistons down if it comes down to it.)

As for the pistons, I would love to run flattop pistons but dished brings me to the comp' ratio I need (depending on what head I choose) and it give's me more room for everything considering the shorter deck, which is a plus.

The cam is actually something I'm still trying to figure out; I want the most I can get out of the block NA before adding Nitrous so I won't have to run as much, however I can't tell if I should use a cam with more lift (above .570) or one with less (.550 and below), so any info regarding the cam helps me a ton!

Luckily, I just finished reading up on rings and how to set them properly, so I have a basic idea of what to do; Before deciding on nos, I was originally planning on a turbo setup but for the most part the rings are set the same; better to have more gap than less.

Thanks for responding guys, it helps me a ton so I don't end up getting the wrong parts, my block has been in the shop for a few weeks now but he can't get much done without the bottom end so it's just been constant phone calls and referrals to other shops who keep referring me to the shop that I just came from lmao
 

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Sounds like a fun build David! just be realistic of what your block can withstand even with a good stud girdle the valley can split in two. Be weary of cam overlap with nitrous man seen too many guys put in a nice choppy cam and have the nitrous backfire through the top end because of low intake velocities...never pretty.
 

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Discussion Starter #7
Right, so get this: Called the machine shop to double check my block deck height so I get the right kit to fit my '69 351w, and the guy simply refused to check the deck height. This is the only shop around me, don't have time to bring the block somewhere else. Not sure what to do honestly, the guy said "It looks like it's never been messed with so it should be 9.480 deck height, I don't know why you're calling me.", though I know there are to many variables that could affect the deck height so, I guess I'm stuck ordering this kit and hoping for the best, not sure what else to do, this throws a kink in ordering the kit unless someone here can give me some pointers for what to do
 

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According to the shop I use, from the factory Ford deck heights were not accurate, nor even equal, to something like 10 or 20 thou. If you want to know it to 0.001" it has to be measured. They always machine them to be equal but it wasn't a very important detail for Ford.
 

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The guy is working for you, if he cant or wont do as you ask find another shop David even if its a little further than youd like to go. Frankly id advise you to send the block to a race type machine shop. they can do a better piston bore finish, balance everything with the flexplate, dampener and answer your questions. Hoping for the best is setting your self up for disappointment man. What if for some reason you have a 10.2 deck block and you put 9.450 stuff in you will have a very poor result.
 
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