351w with decked heads ?

strangeice69 · Nov 14, 2003

the 351w i just bought has the heads decked, what will that change as far as performance. the guy did a complete rebuild. has "mild" cam, reman crank, mild cam, somethin about connecting rods

Turbo II · Nov 14, 2003

strangeice69 said:
the 351w i just bought has the heads decked, what will that change as far as performance. the guy did a complete rebuild. has "mild" cam, reman crank, mild cam, somethin about connecting rods

Depends on how much material was removed, the more that was taken the higher compression..a good thing in moderation (with today's pump gas)

IIRC every thou removed "roughly" translates to one less cc in chamber volume? Or was it every 10 thou

parthos · Nov 15, 2003

maybe the heads were "decked" so that the gasket surface was completly flat. Sometimes when you remove material from the head to gain compression, you end up with funky angles and intake manifolds don't match up anymore, then they have to be "decked" to get them to mate properly. Another consideration is pushrod length. Even though this should be checked with every engine build, it becomes more critical with machining such as this. What you want is the rocker arm centered over the valve at mid lift. Just some stuff to check.

strangeice69 · Nov 15, 2003

ok, its decked 10 thousands. will there be any noticeable gain

strangeice69 · Nov 15, 2003

the guy tore the motor down to build it up and put it in his 89 but plans fell through ...now its MINEEEEEE

zwhitr · Nov 15, 2003

strangeice69 said:
ok, its decked 10 thousands. will there be any noticeable gain

I doubt it only a point or two

now if you deck the block and threw in some flat tops you will then.

but like was said before if you drop your heads down too much your intake manifold won't line up any more.

Wart · Nov 15, 2003

zwhitr said:
but like was said before if you drop your heads down too much your intake manifold won't line up any more.

Then it's better to machhine the intake as they are way cheaper and easier to replace than heads. {Edit} In case the machinest takes too much off or otherwise screws the pooch or if the heads are going to be used on another engine.

BTW, heads are ''shaved' or 'milled', blocks are 'decked'.

strangeice69 · Nov 15, 2003

something was decked....the guy talks to fast and im not up on the technical talk

parthos · Nov 16, 2003

maybe the block was decked. They do this for two reasons, to make sure the piston is flush with the top of the bore, and it provides a flat surface for the gasket to seal to.

strangeice69 · Nov 16, 2003

i hate buying a motor that is partially built up. i never know where to go with it next.

Wart · Nov 16, 2003

strangeice69 said:
i hate buying a motor that is partially built up. i never know where to go with it next.

You also never know if what they say has been done has actually been done, and if it was done how well it was done.

Ask Glenn.

Dano78 · Nov 20, 2003

Normally every engine, block and heads gets decked/milled on a rebuild. BUT- this is only about a .003-.005 decking and/or milling on a normal basis to 'true' up a head or deck surface on the block. If you gotta cut .005 off, you had a pretty seriously tweaked head or deck.

You're close Francis, .008-.010 will give you about 1/4 point in compression on the average. To get a full point you'll need to either cut the block deck .020 or mill the heads. For Mopars i think it's like .012-.014 to get 1/2 a point, which is what i'm toying with at the moment.
Personally if you wanna raise the compression, get the piston with the largest compression height or a dome. If you need to do milling (cost effective) take it from the block. Whan you do that they can mill down the lifter valley rails (at either end where the intake mates) which will enable you to use any intake or head without it needing to be milled. And another thing, for no reason should you mill more than .020 unless you have no other choice or you're going for ubsurd compression. If that's the case, then your intake may have to be milled to correctly line up.

I buy partially built engines all the time. Saves on $$$. You just need to take a little more time and check all the clearances. Hell, the last one I bought, the rods were in backwards (chamfer wrong way and piston notches 1/2 were backwards) Invest in plastigauge and a good ford smallblock rebuilding guide and you won't have a bit of trouble.

As for your mild cam... that's a matter of opinion. Mild to one can be knarly to another. Get the actual specs if you need to. be sure to get the .050 duration numbers. Advertised Duration is a crock and is hardly accurate, especially when comparing other manufacturers' cams.

Reman Crack- Most likely just a stock crank sent out and cut .010/.010 or .020/.020 to refinish the bearing surfaces. No frills. They can cut up to .040/.040 when thay turn a crank, but I wouldn't advise that at all.

He probably 'Reconditioned' or 'resized' the connecting rods. This means the rod and cap mating surfaces were cut down and then bolted together and the hole where the crank would go is then re-machined to a 'true' circle again. And if applicable, you get new bushings on the smaller end if you have floatin pin pistons. Most all SB Fords are press fit pins unless you have some high-end race stuff.

Dano78 · Nov 20, 2003

Wart said:
You also never know if what they say has been done has actually been done, and if it was done how well it was done.

Ask Glenn.

I agree, so you must, check, and check again. Have the proper books and if you not sure, ask questions. Some things, like the boreing or hone job, you'll never know till you fire it up. But the rest of it is all pretty easily measureable. As long as a reputable machine shop did the work, I doubt there will be any problems. It's the fly-by-night garage based machineshops i worry about..

JonDawg · Nov 20, 2003

Dano78 said:
Hell, the last one I bought, the rods were in backwards (chamfer wrong way and piston notches 1/2 were backwards) QUOTE]

Old racing trick. Adds like 30+ Ponies, as long as the piston had an offset wristpin. Only problem is it scrapes the crap outta the cylinder and piston skirt.

zwhitr · Nov 20, 2003

JonDawg said:
Dano78 said:

Hell, the last one I bought, the rods were in backwards (chamfer wrong way and piston notches 1/2 were backwards) QUOTE]

Old racing trick. Adds like 30+ Ponies, as long as the piston had an offset wristpin. Only problem is it scrapes the crap outta the cylinder and piston skirt.

Click to expand...

????

How does it add 30+ Lil mustangs

JonDawg · Nov 21, 2003

zwhitr said:
????

How does it add 30+ Lil mustangs

it changes the rod angle against the crank. That way, the rod pushes harder (sorta) against the crank. more push = more power.

This only works with an offset wristpin though. I know Im gonna get flamed on about this theory1, but I swear to ya that its true. I was in a Mopar 383 before and after, and I makes a REAL difference.

77sleeper · Nov 22, 2003

JonDawg said:
it changes the rod angle against the crank. That way, the rod pushes harder (sorta) against the crank. more push = more power.

This only works with an offset wristpin though. I know Im gonna get flamed on about this theory1, but I swear to ya that its true. I was in a Mopar 383 before and after, and I makes a REAL difference.

that is OLD OLD OLD school I have seen in in a 289 back when vic was running edelbrock

Turbo II · Nov 22, 2003

77sleeper said:
that is OLD OLD OLD school I have seen in in a 289 back when vic was running edelbrock

Thanks! You guys are making feel better (I'm 38 going on 19 )

JonDawg · Nov 22, 2003

Turbo II said:
Thanks! You guys are making feel better (I'm 38 going on 19 )

sorry Turbs, but Im 24, so 38 is old for me of course, I remember thinkin 24 was ancient too.

jeffnoel · Jul 8, 2004

Glenn_MII said:
Furthermore, it's good to see that you still conduct yourself in a polite and friendly fashion.

Great avatar

351w with decked heads ?

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351w with decked heads ?

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