I bought a set of generation I Trick Flow Heads for my 75 L-82. I lucked out and only paid $300. I spent some time this evening checking valve to piston clearance and I was OK on both intake and exhaust (.250 and .300) roughly at the closest points. I called Trick Flow with the serial numbers and got them to e-mail me the specs and installation sheet. Proper length for the Pushrod was noted to be about .100” over OEM. That was pretty close for the exhaust valve. But……….I literally struggled for hours with a gear head buddy trying to determine the length of the Intake Pushrod. Just couldn't get it right. They make no mention of this issue in the specs and instructions. Ended up either too long or too short no matter what we did. Looks like there is some tribal knowledge out there about the need for an offset rocker for the intake valve and some negative feedback about varying pushrod lengths. I bought some nice Lunati 1.5:1 rollers but that isn’t working for the intake. Anyone know any more to help solve the mystery? More info on the offset rocker requirement that is not noted in the instructions?. I am literally struggling with this.

 

Intake valves are 13 degree angle. You need special rockers on the intakes. Been there done that. They flow great. If you have the valve clearance you can use them. You will never get the geometry right with regular rockers. Comp sells them. Look here.
http://www.compcams.com/Products/CC-...kers%27-0.aspx
While your there buy a pushrod length checker for under $20. Set these up right they are great heads.

 

Unless the TF heads are Twisted Wedge, they are like stock as far as rocker arms go.

I have first generation TF heads on my stroker. Nothing unusual about them.

What are the part numbers?

 

Right should have been clearer. The Twisted wedge heads need offset rockers. If the intake and exhaust valves are at different angles this is your problem and 8 new rockers are your solution.

 

I have been involved with 3 builds with the original twisted wedge heads. If you call cutting, re-aligning and welding pushrod guide plates a common engine assembly proceedure, I guess your right. All 3 of these builds were a MAJOR PITA! While they did have decent numbers for flow back in the 90's, the present day AFR and Dart heads flow better with NO rework of the valvetrain and don't put valve notches dangerously close to the top ring land when running big lift cams.

 

I am definitely working with Twisted Wedge Heads. I’ve done some more data mining now and there are a good deal of posts out there even in the Corvette Forum. The Trick Flow Help Line (once again) was little help but did refer me to an engine builder who knew a little about this. There are lots of posts out there now that I know there is an issue and what to look for but many are out of date since these are fairly old heads. The part numbers referenced are typically out of date as well for the set of (8) special rockers (Not sure why they are referred to as Offset) but what Kevin provided is correct for the set of (8) CompCams 1.52:1s (Specific for Twisted Wedge Heads). Thanks much BTW!!!!!!

It looks as though I won’t need to cut and weld any of the Pushrod Guides from what I’ve been able to do so far. The CompCams Rockers should get the Intake Pushrods a little closer to 7.8” with better geometry on the stem but I’ll do the exercise again with the variable length pushrod. Does anyone know if there is a similar (just like the offsets) set of (8) non-offset rockers? .100” over was perfect for the exhaust valve pushrods with regular 1.5:1s so I would guess that using the CompCams offset Rockers on them as well might drive the exhaust pushrod length up even more. Don’t want to end up with too much of a Frankenstein.

I welcome any additional advice ir opinions on this.

 

You use regular rockers on the exhaust. They set up just like conventional heads. Comp has matching 1.52 conventional rockers that match these then you can sell your Lunati rockers to help offset the higher cost of those comp rockers. Trick Flow has never acknowledged these heads need an offset rocker so they will be of no help.

 

Perhaps it's because I've only worked with OEM GM cylinder heads, but your valve clearance seems HUGE. I had my machine shop set intake at .080" and exhaust at .100". I turn 7K rpms regularly and no kissing of reciprocating parts ever.

Are you using a compressed head gasket of the thickness you intend to use during the mockup?

 

Kevin,
Good point. I figured on getting the matching CompCam 1.52:1 Rockers for the exhaust valves and returning the Lunati’s. I think they’re even on the same link page but I’ll call to be sure. I have a valve spring off to take to a machine shop to put on a spring scale. I need 110 lb unloaded and 320 lb open. I need to be sure they will work for my Cam or I’ll need to get a set. If they match up what I need, I’ll be should be ready to go with just the CompCam Rockers.

69Chevy, (couldn’t get your name from your profile)
Another excellent point. We did the clearance tests with the springs removed. We didn’t worry too much about the rocker geometry under those conditions and feel that we still got a pretty good result. Also good point about the gasket thickness. I used the original steel shim from the factory for the test. I have a set of Trick Flow Head Gaskets that will crush to .020 after the torque sequence, so I should be getting fairly accurate results on clearances and geometry. Once I get the right rockers, I’ll size the pushrods with the heads installed and torqued. This will give me exact pushrod lengths to order.

 

I also have an old set of the Twisted wedge heads on my small block......I did run into valve to piston clearence with the larger cam I was using.

When checking on the stand it was real close (dont remember the numbers) but was not interfering so I ran with it. Well it ran for a lil while then one valve broke and that was it. After taking it apart there was evidence of all the valves just barely tapping the pistons.

On the rebuild I wanted to run a larger cam and more compression Trick Flow supplied pistons to match the valve angle but only to 10:1....I wanted more.

I sent the heads off (one seat to get repaired) to get fully ported and polished. Then sent the heads to Ross racing and they made me a matched set of 11:6:1 pistons.

Basically once I got everything back I did not have to run off set rockers....I am running 1:55 full roller comps a Comp solid flat tappet cam....the engine routinely sees 7500 and no issues.

 

Here’s something completely new.

Went to a machine shop today to measure my valve spring Seat Load and Open Load (since these were swap meet heads). (Way too stiff by the way). The guy who ran the shop said he remembered working a set of Gen I Trick Flows some time ago and in addition to the other issues we already know about now, he noted that the set he worked had a recurring problem of sucking oil into the intake valve guide because the guide was constantly under oil. This being because the oil drain holes in the heads were physically above the intake valve guides. I set them up at a 45 degree angle as he suggested and it appeared as though the drain holes were in fact below the Intake Valve Guides.

I haven’t seen one post on the Internet anywhere about this.

Anyone know of or have any info on this problem?

This is critical to me since it will be the make break decision to abandon these heads and go with new Edelbrocks.

 

Never had an issue with that. The Trick flows will outflow the edelbrocks by a noticable margin. If they are in good useable condition and your willing to spring for the offset rockersI would go with them

 

63mako has given you some great feedback to your posts. Keep in mind these heads were developed 15 years ago and technology has come along way expecially in valve seals. With a possitve locking Viton seal you will have no issue with the oiling you are referring to above. He also gave you a great response on the rocker arms. When the heads come out the Comp offset rockers where not available. Now that they are available it does help correct the geometry and you will have no issues.

 

Thanks much guys (everyone) !!!!!!

I found all of the items (Compcams offset rockers for Trick Flow Intake valves and matching set of (8) Rockers for Exhaust valves) and crossed them to Summit. Summit has the best price by the way for anyone interested.

I’m working through the valve spring specs right now. Lunati recommends the following spring {PN 73943} for my 268 Cam (also Lunati):

Lunati Intro Series™ valve spring set
Spring Type: Single w/damper
Outside Diameter: 1.266 in.
Inside Diameter: 0.883 in.
Seat Load: 108 lbs @ 1.750 in.
Open Load: 339 lbs @ 1.250 in.
Coil Bind: 1.060 in.
Spring Rate: 462 lbs/in.

The machine shop boss I worked with in town was reluctant to recommend such a high open load but Lunati insisted that it was right for the cam and I spoke with an engine builder that Trick Flow recommended (worked a lot with Twisted Wedge Heads). Oddly, he had built a lot of motors with the Lunati 60103LK 268 Cam I have and suggested the exact same Lunati springs that Lunati’s Tech people noted. Said he’d installed many of them with that combination.

This seems to check. I looked into what Edelbrock delivers on their outfitted 60899 Head (similar specs to the Trick Flow runners and valve diameters) and the spring they use is EDL 5825. Open Load on that spring is 338 lb. @ 1.27”. I can’t account for the spring rate but it is still pretty similar to the Lunati spring open load at 1.25”.

Thoughts???

 

Here is the spring that was originally on the head. As you can see it has a little bit more seat pressure but less open pressure. This may work very well for the cam since they do not like they open pressure of the Lunati springs.

TFS-16314-16

Number of Springs Per Valve Single
Outside Diameter of Outer Spring (in) 1.250 in.
Coil Bind Height (in) 1.200 in.
Damper Spring Included Yes
Spring Rate (lbs/in) 300 lbs./in.
Inside Diameter of Outer Spring (in) 0.870 in.
Inside Diameter of Inner Spring (in) 0.870 in.
Valve Spring Style Standard

 

Really fast ramp on the Lunati Voodoo series. They need the big spring rate number to control the valvetrain. Use the springs Lunati recommended.

 

Thanks Kevin,

I certainly agree at this point.

Trick flow Tech,
I didn't see Open Load and Seat Load in your description for the TFS-16314-16 Springs. Just the Spring Rate! I have the Head Spec Sheet from TFS and it states:

110 lb. @ 1.700"
290 lb. @ 1.25"

for those Springs

 

Sorry I missed that when I typed it out and I just double checked myself. We have since changed spring manufactures and now use all PAC springs. So now the new 1.250" spring is a little heavier than the old spring that cam on that head.

110@1.780
300@1.280

 

I have a set of these cleaned up and ready to go if anyone is looking for a pair. Decided not to use them, but since doing more research thinking I could have saved some cash by using these instead of replacing with new units. I purchased a whole engine out of a street rod, that as it turned out had a set of rings that had sucked in to the pistons. Heads have new seals, guids, rockers but are without dampers.