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Re: Please Help Deciding On Big Block Heads [Re: Cab_Burge] #2742917
02/14/20 05:51 PM
02/14/20 05:51 PM
Joined: Aug 2011
Posts: 1,852
KATY TEXAS
csk Offline
top fuel
csk  Offline
top fuel

Joined: Aug 2011
Posts: 1,852
KATY TEXAS
Originally Posted by Cab_Burge
Originally Posted by 67mprfan
I see the TF heads have small exhaust valves has anyone thought about putting in bigger valves to help with flow

Why do that when you can increase the exhaust duration, if needed work When the exhaust valve opens it has a bunch of cylinder pressure waiting to escape, open it sooner to let it out longer if needed up twocents
The B1 and B1 MC heads(2.40 intake) both have 1.75 exhaust valves is what I'm remembering scope


Not enough room in a wedge combustion chamber , as Cab said, I'll take a larger intake valve over a larger exhaust valve, to large & they touch.

Last edited by csk; 02/14/20 05:52 PM.

[img]https://live.staticflickr.com/65535/49699175113_7f39889fbc.jpg[/img]87379033_2843330729058951_8904448720599252992_o by Charlie Keel, on Flickr
1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 3.54gear A518 OD 4100lb,11.04@123 full street car trim
Re: Please Help Deciding On Big Block Heads [Re: Cab_Burge] #2742936
02/14/20 07:01 PM
02/14/20 07:01 PM
Joined: May 2005
Posts: 940
ohio
6
67mprfan Offline
super stock
67mprfan  Offline
super stock
6

Joined: May 2005
Posts: 940
ohio
Originally Posted by Cab_Burge

Why do that when you can increase the exhaust duration, if needed work When the exhaust valve opens it has a bunch of cylinder pressure waiting to escape, open it sooner to let it out longer if needed up twocents
The B1 and B1 MC heads(2.40 intake) both have 1.75 exhaust valves is what I'm remembering scope [/quote]

Cab I guess my line of thinking is on 516 heads they have small exhaust valves and 1st thing everyone talks about is putting in bigger valves to help it breathe, I know comparing 516 heads to trickflows isn't apples to apples but they are smaller than Indy EZ's and Victors


71 demon stock stroke 440/indy ez-1 running 10.10 @ 132.14 mph in the 1/4 and 6.36 @ 107.46 mph in the 1/8 not in the same weekend but It did it then I sold it.
67 Belvedere a work in progress
Re: Please Help Deciding On Big Block Heads [Re: 67mprfan] #2742944
02/14/20 07:27 PM
02/14/20 07:27 PM
Joined: Feb 2005
Posts: 15,231
PA.
pittsburghracer Offline
"Little"John
pittsburghracer  Offline
"Little"John

Joined: Feb 2005
Posts: 15,231
PA.
A lot of heads can flow a lot of air with a small valve. Take for example a small block 1.60 exhaust valve on a TrickFlow head. (240 cfm) Keep in mind a 2.02 Edelbrock intake valve out of the box maxes out at 243cfm on my bench. Way off topic but just using this as an example. Many guys would be happy with a 300cfm big block Edelbrock Head.

10B10FD6-08AD-4E2C-BA6C-C11A6AD77C3E.jpeg90BDACE1-C39A-40F9-ABDD-EBF273A90EEA.jpeg

1970 Duster
Edelbrock headed 408
6.143@110.85 mph
9.73@135.05 mph shifting at 6700 RPM
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: Please Help Deciding On Big Block Heads [Re: pittsburghracer] #2742949
02/14/20 07:37 PM
02/14/20 07:37 PM
Joined: Jan 2013
Posts: 174
H
hustlin hoosier Offline
member
hustlin hoosier  Offline
member
H

Joined: Jan 2013
Posts: 174
The heads on our motor flow well over 500cfm. Every time we found flow on the intake we got a good result. We have also spent a lot of money and time on the exhaust side with almost no gain. There is very little hp to be found on the exhaust and with headers. I don't think there is 15 hp between the best set of headers out there and the worst set. I would trade valve size from exhaust to intake anytime.

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