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C8VE heads on stock 91 460 D9TE AB EFI block

10K views 24 replies 4 participants last post by  dirtybird 
#1 ·
I have a set of nicely ported and rebuilt c8ve-e heads, brock performer intake, and 750 carb going on a 91 efi block D9TE AB. Im not replacing cam or pistons at this time. Just merely replacing efi heads and intake with the new set. Im just about ready to remove the heads to install new ones and check new pushrod lenths to order. Now ive been researching and afraid that year block deck height and pistons wont provide enough quench etc and may be prone to detonation. Im hoping to run pump gas at least 92. Im not sure what compression ratio Ill be at?? stock deck height and i dont believe motor has been pulled apart before. Anybody have an idea or has done this to this year block stock???
 
#2 ·
you have that all wrong, the c8 heads have more quench ,if thats what your worried about. this is a swap I have done many times
 
#3 · (Edited)
Rich I think he may be worried about quench distance with the 10.322 block.Dirtybird it shouldn't be an issue if you check to see how far down the hole the pistons are at TDC and choose your head gasket accordingly.Your final compression ratio may be higher than 92 will stand though since the 91 460 should have the shallow dish pistons.You're on the right track with wanting to keep quench dist. fairly tight tho,if it gets excessive it will be more prone to detonation even with a lower compression.
 
#4 ·
john, in this swap it does not matter is my point
 
#5 ·
even mpg will pick up
 
#6 ·
With an oem short duration cam and 10.3 to 1 static c/r with a .070" quench distance...

You had better rethink this.





ENTER YOUR DATA CALCULATED DATA
Cylinder Head Volume (cc)
77
Cylinder Head Vol (cubic in.) 4.697
Piston Head Volume (cc)
6
Piston Head Vol (cubic in.) 0.366
Gasket Thickness (in.)
.041
Swept Volume (cubic in.) 57.481
Gasket Bore (in.)
4.5
T.D.C. Volume (cubic in.) 6.163
Cylinder Bore Diameter (in.)
4.36
Gasket Volume (cubic in.) 0.652
Deck Clearance (in.)
Note: Neg. number above deck, Pos. number below deck
.030
Deck Volume (cubic in.) 0.448
Stroke (in.)
3.85
STATIC COMPRESSION RATIO 10.327
OPTIONAL DATA
Rod Length (in.)
6.605
Adjusted Stroke (in.) 3.491
Intake Closing Point (degrees) ABDC @ 0.050 lift plus 15 degrees
41.5
DYNAMIC EFFECTIVE COMPRESSION RATIO 9.457
Calculate


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#20 ·
With an oem short duration cam and 10.3 to 1 static c/r with a .070" quench distance...

You had better rethink this




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MP how much cam would it take to make this doable with pump gas?Also what is optimal quench distance and does it vary depending on whether you run early heads,D3's or EFI heads?In the process of planning a 427 inch 348 stroker for my 64 K20 the 348-409 guys informed me that by maintaining quench distance at .045 the lack of a combustion chamber in the head allows them to run ridiculously high comp ratios with pump gas.I was just wondering if any of the 429-460 chambers are more tolerant than others.
 
#7 ·
Thank you guys for the quick response! As I am not 100% sure exactly what year van this came off of. I will remove one of the heads this weekend and check piston type, depths, etc. Ill input my numbers here to see if this is doable without removing the block and or replacing the cam at this time. I guess I must say this motor has been in my swamp buggy stock for some time now and was looking to get a little more power outta her. Its already been carburated adpter/carb/hei/etc.
 
#8 ·
Are you using the 1 5/8" 4 hole PMS adapter???



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#9 ·
Mad Porter, I was using an adapter but Im switching to edelbrock performer intake and edelbrock 750 1411 carb.
I just pulled driver side head:
found 88- 92 stock piston with about .02 n change depth relief stock piston.
measured aprox. .021 in the hole.
fel pro gasket kit hs8265pt1 wich i believe is .041 thickness.
remember c8ve head with exhaust porting and new gear.
i confirmed 1990 e250 ford van
i preset the new heads on block and used comp cam pushrod checker and got 8.65 and 8.6 plus the .041 for gasket.
2morro will be removing other head and installing both gaskets/heads.
I did find power steering, alternator brackets 7/16 bolts now need to be 3/8 so ill be picking those up as well.
i have an event in august which im hoping to make even if i have to run hi octane fuel in my 25 gallon tank.
ill pull my motor after with time to work on the block.
What do ya think???
I could pull off a cam swap now b4 event. all i would need to do is remove radiator. if this benefit would outweigh the effort.
ive included some images.
 
#12 ·
THATS MY FAVE STOCK PISTON TO INSTALL A DOVE HEAD OVER
 
#15 ·
I already told you that this is a no go. Especially now that quench is .010" tighter. Are you going to keep asking until you get the answer you want?

Think 96 to 98 R+m / 2




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#17 ·
Sorry to seem terse. I just want to make sure it is understood that this is not pump gas friendly.

I was referring to premium fuel available in the 70's.



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#18 ·
Thanks MP. On my way to reassemble back original efi head and get it running again. Im going to start sourcing out parts to have ready for when i pull the motor.
any recommendations on type of pistons, brand, relief size?

cam recommendation for idle to midrange?

should I do timing chain upgrade for this year 460 90' shortblock? Not sure about these retarded cam timing issues ive been hearing about.

And should the block be 0 decked or other?

Thank you very much in advance, consistent information has been difficult to find up until i stumbled upon this forum.
 
#19 ·
Valve size in your small chamber heads???



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#22 · (Edited)
460 buggy project

Well decided to pull the block off my buggy with limited amount of time and proper tools. My location is far from it and not the most favorable conditions to work in so I have to plan everything carefully. Ill have a proper hoist when block is completed.

I did damage top section of timing chain cover as you can see in the third pic.
 

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