Chevy trick flow twisted wedge heads

[createaaron]

I know these heads are somewhat obsolete today, just picked up a set for cheap that need some repair. Can anyway give me info on how to determine G1 vs G2 heads? Also interested in information on what people have found they flow or can flow.. Thanks

[Prostreetbike]

I have a set of the G1's still new in the box. The G1's have a 13 degree intake valve angle, they had such a bad time with guys trying to run stock rockers on them, which they advertised could be done by the way, that they went to the G2 and that has a 16 degree intake valve angle that you could actually run a stock rocker on. Both the G1 and G2 had a standard 23 degree exhaust angle.
If you have the G1's you must use a .050 back-set rocker on the intake, if you don't you will have valve guide troubles, but he rockers can still easily be found by doing a search for Comp cams twisted wedge head roller rockers. They have them in 1.5, 1.6, 3/8" or 7/16 so that is all good.
I have seen guys say the 13 degree head can go( with pro porting) around 270 @ .500 and as much as 300 @.600, I am not sure of that but it looks like they have some pretty good flow potential.
So if you have a 13 degree intake valve angle they are G1's and if yours have a 16 degree intake valve angle they are G2's.

I have a copy of the G1 installation guide, I will try to attach it...here goes.

[mag2555]

I got these flow numbers from the Stan Weiss site.
All Exh numbers are with 1 3/4" tube on the end of the port so above .400" lift this is adding in 3 to 5% more flow.
G1
.100-----.200-----.300----.400-----.500"----.600"
66--------143------187-----223------232------240
52-------110------148-----178------194------204

G2
68------144------206-----242------252-------257
53------106------144-----173------195-------205

The first set of G1 Trickflows I did if I recall right surprised me by flowing more out of the box then there charts stated, and getting them up to 280 cfm did not take much work!

[Schurkey]

"Raised" guideplates = G1
"Flat" guideplates = G2

Of course, some applications (self-guided OEM rockers) did not have guideplates.

I have heard--but not verified--that excessive guide wear on G1 heads can be due to not machining the spring pocket "flat" in relation to the valve guide angle.

[createaaron]

My plan with these heads is to replace the cast iron valve guides with bronze guides and re-machine the valve spring pocket perpendicular with the valve. Doing this with the proper rocker should net a long life. I haven't looked very far into them but I will probably port them. Any ideas for making a guide plate to accept a 3/8 pushrod?

[shoedoos]

don't lose or destroy the existing guideplates on your trickflows......they are truly hen's teeth....

[mag2555]

You might start off with Edelbrock 9666 plates and cut & weld them as needed?

[shoedoos]

Mag2555 could be on to something.....maybe try the Dart BBC adjustable guideplates and modify them....

[Schurkey]

The trick will be to get Comp Cams to build TFS-Twisted Wedge G1 rocker arms in self-guiding versions.

[68post]

I got these flow numbers from the Stan Weiss site.
All Exh numbers are with 1 3/4" tube on the end of the port so above .400" lift this is adding in 3 to 5% more flow.
G1
.100-----.200-----.300----.400-----.500"----.600"
66--------143------187-----223------232------240
52-------110------148-----178------194------204

G2
68------144------206-----242------252-------257
53------106------144-----173------195-------205

The first set of G1 Trickflows I did if I recall right surprised me by flowing more out of the box then there charts stated, and getting them up to 280 cfm did not take much work!

That is interesting , I have a set of these (Gen 1) on the shelf. Some have said the same as you've said , even close to 300 cfm with a port finished around 190cc !

[mag2555]

The 13 degree intake angle can be tricky to port though if you have never done many Ford FE heads , or Pontiac and such to high flow levels ( 50 or more cfm over stock) as flow separation and reverse high lift numbers comes up to rear its head much sooner and you need to know how to deal with it!

[shoedoos]

https://www.ebay.com/itm/Adjustable-Gui ... SwoXRZke~9

[tt 383]

Some 1 on here posted that merely removing the ramp got them to about 275-280. I know they are a finicky head and not intended for racing perse, but it would be in interesting to me at least to see a max port, high comp 383-406 build to see potential. All I have ever seen are low comp 305-355 builds. You got any specifics you could share Mag?

[rfoll]

I have a set of guide plates I have no use for if anyone is interested.

[mag2555]

In terms of the heads themselves the width of the floor and the overall arc of the short turn need to be right once a certain air mass / port velocity is moving into the chamber.
I will see if I have notes on this on my flow sheets from porting these Heads tonight and post back to you tomorrow.