Head Swap Build Thread: And other Improvements

[revhead347]

Seems like the mid pipe is going to be a big hang up. Maybe I'll just order a mid pipe and hope I get lucky or that it wont require to much fab work.

What exactly are you worried about on the midpipe. If you are worried that the distance between the tubes won't be right to match up to the headers, don't be. It doesn't matter what setup you have they never match up. But you can bend them real easy to fit. Last time I did it with a ratchet strap.

Kurt

 

[Venom351R]

yeah thats what I was worried about is the width across more so then the length b/c to add or take away to make it shorter or smaller seems more easy then if it was not to line up at all.

I'll probably go ahead and just buy a standard mid pipe then and and hope for the best, if all it took was ratchet straps then I guess I should not be to bad off. As far as the headers Id rather just stick with the Accufab since I know I wont have any clearance issues ( I as well have the 3550 ) since they can fab it up exactly for my set up. It seems as though the mid pipe issue wont be as much of a problem as I first thought.

I have to pick up some teflon thread sealant anyway b/c Ed said to use it to screw in the rocker studs

 

[revhead347]

I'm only bringing up the Mac and BBK stuff, because I've seen a few Accufab isntallations, and they seem to hang too low. The BBK headers stay nice and close to the body where they won't scrub on everything you go over.

Kurt

 

[Venom351R]

Well I dont need an erg tube bung anyway all that has been removed

 

[Venom351R]

As long as their headers would bolt to my heads I'd be ok with going with those bc bc then I know I wouldn't have mid pipe issues

 

[revhead347]

Dude, I totally forgot you had a 351, so that's out. Any foxbody header should work, because you have a TR-3550. The interference difference between the Fox and the SN is the clutch fork, so it shouldn't be an issue since you have a Fox style transmission.

Kurt

 

[Adam95GT]

Dude, I totally forgot you had a 351, so that's out. Any foxbody header should work, because you have a TR-3550. The interference difference between the Fox and the SN is the clutch fork, so it shouldn't be an issue since you have a Fox style transmission.

Kurt

He still has an issue with the 3/4'' raised exhaust ports.

my accufabs couldnt tuck the body any closer:

 

[revhead347]

He still has an issue with the 3/4'' raised exhaust ports.

my accufabs couldnt tuck the body any closer:
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Those look pretty good actually. I have the raised ports as well, and they aren't an issue with the BBKs. Not sure how it will work with the 351. Too many variables in this equation.

Kurt

 

[Venom351R]

Ugh. I hate going on hoping it will work, it's better to just go with the assufab and know it will work. I don't have a lot if wiggle room fir getting this together tuned and to the track before it's winter time here. I'm already looking at august as long as I have no delays and dealing with header fitment issues would mess that all up

 

[Venom351R]

Ok so I did a check on the PVC tonight when I got home, I just want to make sure if you guys think this is right or not considering it barley left an imprint in the clay. I had the clay at the thickness of the dish in the piston and the intake valve barley left any mark into the clay and the exhaust I don't think left anything. Just want to know if this is out of the ordinary or not or if I didn't do it correctly. From what it looks like to me there is plenty of clearance. Also the clay was around the whole ouside formation of the dish in the piston and you can also see that it would not hit on the area of where the dish ends and it goes back up to the flat part of the piston.

Also what do you think of the pattern left on the top of the valve spring as far as pushrod length?

 

[Adam95GT]

push rods are a hair short. You also have a large contact patch by the looks of it.

 

[Venom351R]

What does a large contact patch mean? I do have an adjustable push rod length checker I wanted to see how my previous ones looked. What do you think of the PVC?

 

[blksn955.o]

I think the the pattern is a tad too wide like said but when you get the length sorted out the line should narrow out a little. The patch is wide as the rocker roller is traveling across the valve head instead of pushing the valve down.

This is why you look for a centered narrow contact pattern that stays narrow while in travel. It means the rocker is staying centered and putting its force directly to the valve and little energy is being wasted by the rocker traveling across the valve head surface.

 

[blksn955.o]

If the PR is in fact too short then give the adj checker a 1/4 turn and go threw the cycle again. Its a repeated process until you get the line centered and travel pattern as narrow as possible.

It could also be helpful to bring the cam to mid lift and see were the contact patch is. It will probably give you a clearer measure as to were your rocker is actually sitting on the valve head as there will always be travel but by checking at mid lift the rocker should be center of the valve head. If its centered at mid lift...the pattern is going to be what the pattern is but you know your rocker is at the center of the valve at its mid point (mid travel). It will also save you a metric ton of time rotating the motor. You just have to setup a dial on each cyl. you check to measure for mid lift.

 

[Venom351R]

I don't have a dial so I'll have
to just keep doing it the low tech way. When it warms up today I'll go out and try it out with the adjustable PR checker.

I bought a digital caliper but the imprint was so minimal that it does not appear that the valve is even going in the pocket in the piston. Is this common or normal?

 

[YEAHLOH95]

from the look s of it your piston to valve seems ok hoth thisck is the clay under the mark that the valve left

 

[Venom351R]

I got done using the adjustable push rod checker. Ended up turning it 3 turns from the stock length push rods that I had before. They were 7.60 so 3 turns would be 7.75. This is the best I have gotten it so far, its more in the middle then it was. The thickness of the mark has gotten thinner and the location on the top of the valve has improved. does it still need more length to it or am I good where I am? Also I checked the PVC again with the 7.75 PR length and this is what I came up with.

INTAKE VALVE

 

[revhead347]

That valve pattern looks perfect. Order them up.

Kurt

 

[blksn955.o]

I agree the pattern looks good to go.

I don't know how much for stud mount this matters but with a solid lifter you need to remember to add some to the PR length to make up for the missing pre-load.

How thick is the clay from the deepest part of the valve impression to the piston?

 

[Adam95GT]

Still a little wide but your right where you want to be. What rocker arms? Have you checked alignment of the guideplates?