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 Post subject: Let's talk valve sizes
PostPosted: Sat Jul 18, 2009 9:28 pm 
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EFI Slant 6

Joined: Fri Feb 15, 2008 8:17 am
Posts: 329
Location: Seymour, TN
Car Model: 1965 Dart 270 w/ 66 Valiant front clip
Ok, So far I've heard of the following valves used in /6 heads:

*ford 300 six valves
*BB mopar valves (dont recall which sizes though, can anybody shed light
on this? I have a couple of BB mopar heads laying here)
*The common 1.70/1.44 valves

What are your experiences and gains (as in how much more noticeable)?

Im intrested in the BB mopar setup because I'm poor and that's what ive got laying about :roll:


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 Post subject:
PostPosted: Sun Jul 19, 2009 7:08 am 
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Board Sponsor & SL6 Racer
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Joined: Sun Jul 30, 2006 8:36 pm
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Location: East Arkansas
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The 1.70/ 1.44 is the cheapest way to go for "new" valves. The Ford valves are not the same shaft size, 3/8 vs 7/16. I also think the BB need cut down to fit a slant head.
My02.
Frank

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 Post subject:
PostPosted: Sun Jul 19, 2009 7:29 am 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
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Location: IRWIN PA
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I posted a similar question:

http://www.slantsix.org/forum/viewtopic ... tive+valve

check it.


Greg

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 Post subject:
PostPosted: Mon Jul 20, 2009 6:38 pm 
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EFI Slant 6

Joined: Fri Feb 15, 2008 8:17 am
Posts: 329
Location: Seymour, TN
Car Model: 1965 Dart 270 w/ 66 Valiant front clip
What needs to be done to the 1.70/1.44's? Are they really drop in's??


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 Post subject:
PostPosted: Mon Jul 20, 2009 7:35 pm 
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Supercharged
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Location: IRWIN PA
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Get the Head cut to match the valve size

yes they are drop in besides that.


Greg

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 Post subject:
PostPosted: Wed Jul 22, 2009 8:33 am 
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EFI Slant 6

Joined: Fri Feb 15, 2008 8:17 am
Posts: 329
Location: Seymour, TN
Car Model: 1965 Dart 270 w/ 66 Valiant front clip
Wasnt it Charrlie S. that was using backcut stock valves??

Just weighing in all the options for best bang for the buck.


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 Post subject:
PostPosted: Wed Jul 22, 2009 8:58 am 
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SL6 Racer & Moderator
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Joined: Sat Oct 19, 2002 12:06 pm
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Location: Silver Springs, Fl.
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I had a stock rebuilt head on my "low buck" 66 valiant. I had a fresh head on the shelf, that I had milled, to put on the car as an "upgrade". While I had the milled head apart to put stiffer springs on it, I decieded to backcut the valves (I have a valve grinder). I would not recommend just back cutting the stock valves, it will give a small gain, but not worth doing just that. I would recommend doing a back cut, and opening up the bowls together.

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 Post subject:
PostPosted: Tue Aug 11, 2009 10:16 pm 
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EFI Slant 6

Joined: Fri Feb 15, 2008 8:17 am
Posts: 329
Location: Seymour, TN
Car Model: 1965 Dart 270 w/ 66 Valiant front clip
I became curious also about the ford 300 six valves. What are the valve sizes on these? (1.78, 1.56??) and also other than enlarging the valve seats- is any other work required?? Could 340 springs work with these??

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Michael Glass. Mopar stuff and some rusty Mopar stuff!
1965 Dodge Dart with 66 Valiant front clip. Other stuff...


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 Post subject:
PostPosted: Wed Aug 12, 2009 5:33 am 
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Board Sponsor & SL6 Racer
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Joined: Sun Jul 30, 2006 8:36 pm
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Location: East Arkansas
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The stem size on the Ford valves is 11/32 so you have to rebush the guides. You will also have to adjust the stem height. The springs are dictated by cam choice as well. So what lift cam are you running? Also on another note how big an overbore are you planning as these valves need BIG bores to deshroud them.
Frank

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73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered


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 Post subject:
PostPosted: Wed Aug 12, 2009 9:16 am 
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EFI Slant 6

Joined: Fri Feb 15, 2008 8:17 am
Posts: 329
Location: Seymour, TN
Car Model: 1965 Dart 270 w/ 66 Valiant front clip
Quote:
The stem size on the Ford valves is 11/32 so you have to rebush the guides. You will also have to adjust the stem height. The springs are dictated by cam choice as well. So what lift cam are you running? Also on another note how big an overbore are you planning as these valves need BIG bores to deshroud them.
Frank
Im thinking .080 over at least, with the use of a .528 cam.

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Michael Glass. Mopar stuff and some rusty Mopar stuff!
1965 Dodge Dart with 66 Valiant front clip. Other stuff...


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 Post subject:
PostPosted: Wed Aug 12, 2009 5:16 pm 
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Turbo Slant 6
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Joined: Fri May 08, 2009 5:44 pm
Posts: 721
Location: Reno NV
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Not to hijack your thread,but what is the biggest valve size you should be able to run with a .060 overbore?


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 Post subject:
PostPosted: Wed Aug 12, 2009 5:29 pm 
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Joined: Mon Mar 31, 2003 1:04 pm
Posts: 7452
Location: Oregon
Car Model: 2023 Eichman Digger?
Anything beyond the 300 ford valve is going to be shrouded by the bore itself. Minimum overbore is .060" when using these valves. Mine is .045" over, and I tagged the cylinder walls with three of my exhaust valves. Mock up the cylinder head to the block and verify the combustion chambers are correctly aligned over the cylinders before bolting things up. You may need to use offset alignment dowels to correctly position the head.
One of the tricks when using valves of this size is to notch the bores slightly where the valves come close. Just don't notch down where the top ring rides in the bore. Stay above it for obvious reasons. It doesn't take a big cut, just enough to make sure there is clearance.

CJ

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 Post subject:
PostPosted: Wed Aug 12, 2009 5:36 pm 
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Turbo Slant 6
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Joined: Fri May 08, 2009 5:44 pm
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Location: Reno NV
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I heard/read that if you do not cut the head,and only clean the surface up that you may not have issues.Just mill the deck for more comp. I wish we had high compression pitsons readily availible like the small block guys. Sounds like I may need to notch the chamber and the bore if I want to go bigger than the ford valves,correct?


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 Post subject:
PostPosted: Wed Aug 12, 2009 9:23 pm 
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6 Pack Dart
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Joined: Sat Nov 02, 2002 5:44 pm
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Location: Eugene, Oregon
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This is what your head looks like with Ford 300 Cu In valves.

Image

There isn't enough room to go much bigger!!

Image

Then you can do this, picture doesn't show final of work done

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 Post subject:
PostPosted: Wed Aug 12, 2009 9:38 pm 
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Supercharged

Joined: Thu May 12, 2005 11:50 pm
Posts: 6291
Location: So California
Car Model: 64 Plymouth Valiant
Quote:
This is what your head looks like with Ford 300 Cu In valves.

Image

There isn't enough room to go much bigger!!

Looks like you'd have a shrouding problem going that big...........

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64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

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