Don Terrill’s Speed-Talk

OK...instead of posting several new questions about my Mopar build here, and plugging up the forum, I'll try to ask on one post and see where it goes.

I am using a set of W-2 "econo" heads on my 388 dirt track engine. These have had the rocker stands milled off and I have bothe stock Mopar rockers (with billet stands) and new T&D rockers.

The heads I have were made to use 3/8" stem 5.05 length valves on both intake and exhaust. The race "long valve" version of these heads usually take a 3/8" stem 5.30 valve. (There are some variations on these heads as produced by Mopar but this is kinda of an accepted starting point).

Any reason to but the longer 5.30-ish valves when using a cam of .600 lift? The installed height on my present valve springs is 1.8 with coil bind at 1.2-ish.

The rockers were shimmed to get proper sweep on the valve stem tips. They used a hardend 38" flat washer as a shim.

I also want to switch to beehive or conical springs and get a slightly lighter rated spring. I now have a 400 open/160 closed set of triples.

Tonite I plan on taking a couple pix of the intake and exhaust ports, too as I would like opinions on the SSR and valve stem protrusions into the bowl to see if I can make any worthwhile improvements in my shop. I hope to have one head flowed at a local shop next week. I know what the flow #'s were as told by the PO but I'd like to see what another flow bench sez.

I also have one valve that had a gooey, oily deposit on the back of one intake valve. Kind of perplexing to find on one valve in a relatively short time engine.

Can anyone tell me if this looks like a Manley Race Flow intake valve? The shop who did the first build used a lot of Manley and Crower parts when this was built mid-90's.

Your opinions are always welcomed...

The only differences between the "Econo" head machined castings and "Long Valve Race Heads" were the rocker shaft height and bolt down locations.

Those bolt holes were machined back from the valves toward the intake flange on the "race" heads along with the semi-circle stand mounting face being machined slightly higher.

Walter R. Malik wrote: ↑Sat Jan 04, 2020 9:52 pm The only differences between the "Econo" head machined castings and "Long Valve Race Heads" were the rocker shaft height and bolt down locations.

Those bolt holes were machined back from the valves toward the intake flange on the "race" heads along with the semi-circle stand mounting face being machined slightly higher.

I often forget about the bolt holes being moved back... thanks for the heads up.

Walter R. Malik wrote: ↑Sat Jan 04, 2020 9:52 pm The only differences between the "Econo" head machined castings and "Long Valve Race Heads" were the rocker shaft height and bolt down locations.

Those bolt holes were machined back from the valves toward the intake flange on the "race" heads along with the semi-circle stand mounting face being machined slightly higher.

The only difference between the Econ head and the race head is the length of the valves and method of securing the shafts.

The Econ head uses saddles and the race head uses blocks and stands. They can either be centered holes of offset holes in the shafts and stands.

The holes in the heads are the same.

You now effectively have race heads. As long as you use the long valves. If you weren't going to use long valves, you should have just left it alone.

ClassAct wrote: ↑Sat Jan 04, 2020 10:56 pm


The only difference between the Econ head and the race head is the length of the valves and method of securing the shafts.

The Econ head uses saddles and the race head uses blocks and stands. They can either be centered holes of offset holes in the shafts and stands.

The holes in the heads are the same.

You now effectively have race heads. As long as you use the long valves. If you weren't going to use long valves, you should have just left it alone.

The cast iron pedestals on the race heads were machined off after the first run so, after that the heads were essentially the same.
the very first long valve W2's from the late 70's had cast iron stands with higher semi-circle machining and moved bolt holes.

I owned a pair. You can believe whatever you want.

ClassAct wrote: ↑Sat Jan 04, 2020 10:56 pm

Walter R. Malik wrote: ↑Sat Jan 04, 2020 9:52 pm The only differences between the "Econo" head machined castings and "Long Valve Race Heads" were the rocker shaft height and bolt down locations.

Those bolt holes were machined back from the valves toward the intake flange on the "race" heads along with the semi-circle stand mounting face being machined slightly higher.

The only difference between the Econ head and the race head is the length of the valves and method of securing the shafts.

The Econ head uses saddles and the race head uses blocks and stands. They can either be centered holes of offset holes in the shafts and stands.

The holes in the heads are the same.

You now effectively have race heads. As long as you use the long valves. If you weren't going to use long valves, you should have just left it alone.

All this work was done years ago when the engine was first run. I'm rebuilding it after being run for two partial seasons, stored, then loaned out then blown up.

I was just getting info on the pros/cons of switching to long valves. Seems like there will be no advantage to making the switch with the lift cam I'll be using. If I was using a big lift cam the answer might be different.

Update....looking at the stands that were last used (cast iron adj. rockers) I can see the hole is offset. Stock valves with stands made for long valves...hmmm.

I also have T&D rockers/shafts but do not have stands. Looks like I need to do more detective work.

Comp Cams has a large range of beehive & conical springs to choose from.

In stock form if I recall right from working on iron W2s the heads flow between 245 and 260 on the Intake side and like 165 on the Exh.
With your cid you should have little trouble making between 475 and 490 hp even with only 260 cfm of flow.

I would with out question go over to 11/32 stem valves to get a ton of weight off of that side of the spring and attain better valve control with less pressure.

I have ported these iron heads up to 290 cfm @ 28" with a 2.08" valve with no loss of air flow at lower lifts like what takes place when you shoot for Intake flow numbers above 310 cfm.

The port walls on these iron are solid for any type of usage you can throw at the head with limiting porting work to 290 cfm.

Note that the port runner does need to go from a oval shape to rectangular even to get to 290 Intake cfm.

I’ve had several sets of W2’s in the shop through the years.
Some new ootb, some previously reworked.

All the ootb ones I’ve had here had noticeably different port bias on the intake ports, so there would be noticeably different flow between left/right intake ports.
#1 will have the port biased for flow towards the center on the bore......#3 will be towards the cylinder wall.

If you’re having a head tested, test both a left and right intake port.
Only testing one may not be giving you the whole picture.
It’s often a case of...... what it flows ends up being determined by the lift point at which it goes turbulent.

The pic of the intake valve laying on the bench, by the looks of the thickness of the margin...... it appears to be a valve that was cut down from a larger OD.

If you swap to 11/32 stems, there are a lot of steps in between 5.050 and 5.300.

If you’re serious about the beehive/conical springs....... you should buy a retainer for mock up purposes.
They often have less installed height than their std counterparts.

Walter R. Malik wrote: ↑Sat Jan 04, 2020 11:59 pm

ClassAct wrote: ↑Sat Jan 04, 2020 10:56 pm


The only difference between the Econ head and the race head is the length of the valves and method of securing the shafts.

The Econ head uses saddles and the race head uses blocks and stands. They can either be centered holes of offset holes in the shafts and stands.

The holes in the heads are the same.

You now effectively have race heads. As long as you use the long valves. If you weren't going to use long valves, you should have just left it alone.

The cast iron pedestals on the race heads were machined off after the first run so, after that the heads were essentially the same.
the very first long valve W2's from the late 70's had cast iron stands with higher semi-circle machining and moved bolt holes.

I owned a pair. You can believe whatever you want.

I have the engineer drawing for BOTH W2 and W5 heads and the bolt holes are in the same location and ironically, the bolt location is the SAME as production heads.

Jesus. You can take a production head and a W2 head and set them side by side and measure it. They are the same. All they did was mill the stands. In fact, the small block engine book gives the measurements to machine the stands. It's for production heads too.

ClassAct wrote: ↑Sun Jan 05, 2020 12:04 pm

Walter R. Malik wrote: ↑Sat Jan 04, 2020 11:59 pm
The cast iron pedestals on the race heads were machined off after the first run so, after that the heads were essentially the same.
the very first long valve W2's from the late 70's had cast iron stands with higher semi-circle machining and moved bolt holes.

I owned a pair. You can believe whatever you want.

I have the engineer drawing for BOTH W2 and W5 heads and the bolt holes are in the same location and ironically, the bolt location is the SAME as production heads.

Jesus. You can take a production head and a W2 head and set them side by side and measure it. They are the same. All they did was mill the stands. In fact, the small block engine book gives the measurements to machine the stands. It's for production heads too.

There was no such thing as W5 heads in the 70's.
Again, you can believe whatever you want. I don't really care as it makes no difference to me.

Looking at the pics a bit more....... heads are machined for o-rings?

PRH wrote: ↑Sun Jan 05, 2020 5:35 pm Looking at the pics a bit more....... heads are machined for o-rings?

Yep...they did use o-rings on the initial build. 13 1/2 - 1. Switched to 1008 Fel-Pro's after the first cam bit the dust. This build was first done in '93... broke in 2007. Lots of new gasket tech since then as you know.

PRH... I was looking thru some info on T&D's web page and they say their rockers for the W2 are made for 5.140 valves. I have a set that came with this engine but they were never used. Had ductile iron adjustables on it. I'm going to use the T&D's. So there's another variable for valves. I'm glad I got that info. I'll call them before I order valves just to be sure that is correct today. Might get a couple samples in different lengths just to see what works best.

As far as the valve margin I couldn't tell you. I believe these are Manley Race Flow valves. The shop that did the motor used Manley wherever possible I have been told. The Ti retainers and locks as well as the springs are Crower. Maybe they started with 2.08's?

Walter R. Malik wrote: ↑Sun Jan 05, 2020 5:26 pmnu

ClassAct wrote: ↑Sun Jan 05, 2020 12:04 pm

Walter R. Malik wrote: ↑Sat Jan 04, 2020 11:59 pm
The cast iron pedestals on the race heads were machined off after the first run so, after that the heads were essentially the same.
the very first long valve W2's from the late 70's had cast iron stands with higher semi-circle machining and moved bolt holes.

I owned a pair. You can believe whatever you want.

I have the engineer drawing for BOTH W2 and W5 heads and the bolt holes are in the same location and ironically, the bolt location is the SAME as production heads.

Jesus. You can take a production head and a W2 head and set them side by side and measure it. They are the same. All they did was mill the stands. In fact, the small block engine book gives the measurements to machine the stands. It's for production heads too.

There was no such thing as W5 heads in the 70's.
Again, you can believe whatever you want. I don't really care as it makes no difference to me.

No shit? No W5 heads in the 70's? I didn't know.

Again, the hold down bolts on a Chrylser small block head are in the same location for a production head, a W2 AND a W5. The W2 and W5 take the EXACT same valve gear.

So you are speaking an error. Unless you had some preproduction heads that no one else has, all the heads I just listed have the rocker shaft hold down bolts in the exact same location. You are WRONG.

Damn.

Try this guy, big on valve train issues with W2 heads.
http://www.b3racingengines.com/