Fix my W2s or go with RHS heads?

[rmchrgr]

Wow, thanks for the detailed reply, Myron. Good info. I appreciate you thinking all that through and typing it out.

Here's some more info on the rest of the combo

340, stock stroke
aforementioned #810 iron heads
not sure on pistons but compression test was around 175-180 psi
runs on pump 93, sometimes mix with Cam 2 100 unleaded
TTi 1 7/8 step headers
MP .557 cam lashed to .026" intake, .028" exhaust
Harland Sharp W2 rocker arms
Victor W2 intake
Proform 750 D.P. 76/86 jets, 4.5" P.V. in front, #37 pump nozzles
RobbMc pickup in stock tank
3/8 fuel line
Carter mechanical strip fuel pump
4.10 gear with Auburn Sure Grip
Caltracs w./ split monos, Rancho shocks front and rear
275/60 (28") M/T drag radials
904 with T.A. FMVB, no engine braking in first, low first gear set
not sure on the converter but its a Hughes Performance 3,800 or so
MSD ignition
Autolite 3428 (3824?) plugs gapped @ .040"
MP mechanical advance distributor, 20 initial, 36 total all in by 2,000 rpm
car weighs around 3,000 without me, I am 180.

Theoretically, with everything working right, this should be a solid, mid-to-low 11 second car. I didn't think I'd lose much if anything going to the RHS heads, especially if I stay with a single plane intake.

 

[moparlover]

Here's a chart from Hughes webpage for 'Super Prepped' RHS heads with 2.02 intake valves. Probably similar to what IMM does.

Lift Stock Super Prepped CFM Change Stock Super Prepped Change
.550 262 271

Here's an older chart for unported W2s from SDSS. This chart is for a 2.02" intake valve so the larger valve that I have will probably yield slightly better results. Clearly the potential is there for some big numbers but it's going to take a lot of grinding ($$) to get 'em there.

LIFT--------AS-CAST---------PORTED
.550”------258.4/155.2---------303.9/213.9

See the dilema? They're pretty close if you're racing flow benches. Besides, my cam only opens the valve .531" after lash so anything over that is irrelevant.

depending on your compression ratio, a replacement .557 cam + W2 port / valve repair would be noticeable

you may only need some valves not all valves but your current springs are probably tired anyways it would be a good time to re-cam/re-spring since you are redoing the heads anyways

a .590 cam would be a huge step

 

[rmchrgr]

depending on your compression ratio, a replacement .557 cam + W2 port / valve repair would be noticeable

you may only need some valves not all valves but your current springs are probably tired anyways it would be a good time to re-cam/re-spring since you are redoing the heads anyways

a .590 cam would be a huge step

Kind of trying to avoid a total rebuild though that would ultimately be the best idea. I can replace the heads with the short block still in the car and without taking the timing cover off.

Was thinking about new springs but again, I'm getting into more cost. I'd also be getting retainers, keepers and seals. When I was working as a tech, we rebuilt heads all the time, all that stuff was the minimum on regular, every day production cars. The RHS heads come with all that so that's included in the total cost.

Again, I don't imagine I'd be giving up a whole lot with the RHS heads over the unported W2s. I know it's an apples to oranges comparison but for the power level I am at (425-450hp) I think it's a reasonable choice.

Still undecided but keep the info coming.

 

[Locomotion]

Wow, thanks for the detailed reply, Myron. Good info. I appreciate you thinking all that through and typing it out.

Here's some more info on the rest of the combo

340, stock stroke
aforementioned #810 iron heads
not sure on pistons but compression test was around 175-180 psi
runs on pump 93, sometimes mix with Cam 2 100 unleaded
TTi 1 7/8 step headers
MP .557 cam lashed to .026" intake, .028" exhaust
Harland Sharp W2 rocker arms
Victor W2 intake
Proform 750 D.P. 76/86 jets, 4.5" P.V. in front, #37 pump nozzles
RobbMc pickup in stock tank
3/8 fuel line
Carter mechanical strip fuel pump
4.10 gear with Auburn Sure Grip
Caltracs w./ split monos, Rancho shocks front and rear
275/60 (28") M/T drag radials
904 with T.A. FMVB, no engine braking in first, low first gear set
not sure on the converter but its a Hughes Performance 3,800 or so
MSD ignition
Autolite 3428 (3824?) plugs gapped @ .040"
MP mechanical advance distributor, 20 initial, 36 total all in by 2,000 rpm
car weighs around 3,000 without me, I am 180.

Theoretically, with everything working right, this should be a solid, mid-to-low 11 second car. I didn't think I'd lose much if anything going to the RHS heads, especially if I stay with a single plane intake.

Just a few thoughts/observations/2 cents:

1) TTI 1 7/8" headers are straight. Their stepped version is 1 5/8"-1 3/4" step. The stepped headers "might" be holding you back a little, but they are pretty versatile and will help with bottom end & midrange.

2) A good quality looser converter would help. But you may need to work on the suspension to handle it.

3) Double check the shocks up front. Rancho shocks, if any fit, should not be used up front. But their old 5 or new 9 way are good for the back. Cal-Trac has their own versions now.

4) The Edelbrock Victor has a larger plenum than othe intakes, such as the Holley Strip Dominator. I normally ran the Holley. If you have or will use a spacer, stick with a 4-hole or tapered 4-hole.

5) A little more gear may help. Trap RPM should be a bit over optimum shift RPM. But I wouldn't be concerned about shifting much over 6,800.

6) Check valve spring pressures. 140+ seat/340+ open. Others may offer their own suggestions.

7) Make sure you have enough fuel pressure & volume. Personally I never cared for a mechanical pump on drag car.

8) Experiment with pump cams & squirters for better 60' times. Jet for MPH. It might be easier to remove the power valve and jet square. Experiment from there. 86 seems rich, but I don't know what the Proform recommendations are. 4779 Holleys are like 72/81 with a power valve. (I'd have to look it up.)

Something, or things, are holding you back so you need to stay conservative and double-check what you have, mainly in the engine. Can't take for granted that everything was correct when you got it.

 

[rmchrgr]

Just a few thoughts/observations/2 cents: 1) TTI 1 7/8" headers are straight. Their stepped version is 1 5/8"-1 3/4" step. The stepped headers "might" be holding you back a little, but they are pretty versatile and will help with bottom end & midrange.

I could be wrong about the headers, I may have the wrong nomenclature. I looked on the TTI site, I can measure the collector diameter to determine which ones I have. The larger diameter have 3.5" collectors as opposed to 3". Looks like I may have the 1 7/8 version based on their pic but who knows if its accurate.

2) A good quality looser converter would help. But you may need to work on the suspension to handle it.

I agree with that. If I built the car, I would have probably got a custom converter.

3) Double check the shocks up front. Rancho shocks, if any fit, should not be used up front. But their old 5 or new 9 way are good for the back. Cal-Trac has their own versions now.

Again, incorrect nomenclature. I have the Calvert 90/10 shocks up front. Measured with a floor jack under the k frame, I have almost 5" of travel from rest to full rise.

4) The Edelbrock Victor has a larger plenum than othe intakes, such as the Holley Strip Dominator. I normally ran the Holley. If you have or will use a spacer, stick with a 4-hole or tapered 4-hole.

i thought about a spacer but I don't think it would fit under my flat hood. I could run sans air cleaner but I'd rather not. Might see if I can get one under there.

5) A little more gear may help. Trap RPM should be a bit over optimum shift RPM. But I wouldn't be concerned about shifting much over 6,800.

Funny, I took the 4.30:1 gears out that were in the car. I had built an aluminum center 4.10 gear several years ago for another project that I wanted to use. I noticed a difference on take off but nothing dramatic, it's only a small percentage change.

6) Check valve spring pressures. 140+ seat/340+ open. Others may offer their own suggestions.

I was planning to do that. I don't have a spring tester, guess I might need to look into one. Any Rimac is going to be over $400. have you ever used the Proform ones you stick in a vise?

7) Make sure you have enough fuel pressure & volume. Personally I never cared for a mechanical pump on drag car.

That Carter strip pump actually needs a regulator. When I first got the car, the fuel pressure was way high, like 12 psi, it was super rich. According to the little gauge on the carb inlet line, its at 7 psi now. !/2" pickup in the tank, 3/8 line (I know, it is what it is).

Experiment with pump cams & squirters for better 60' times. Jet for MPH. It might be easier to remove the power valve and jet square. Experiment from there. 86 seems rich, but I don't know what the Proform recommendations are. 4779 Holleys are like 72/81 with a power valve. (I'd have to look it up.)

I need to get different squirters, I think the 37s I have in there are too big, maybe 33s. Initially it had the pink cam but I went to the red cam. The pink was like 'right now' then flat, the red seemed a little smoother but I was getting the lean spike with the red. I have an A/F gauge with a data recorder and it showed a lean spike before I'd shift, like almost 20:1 but only for a second. Then it shifts and goes back down. Cruise is pretty good between 12.5-14.7 depending on throttle position. 53 MPH seems like the sweet spot - 3,000 rpm almost perfect A/F at 14.5. A higher number power valve made it surge while cruising. OOTB, the carb had 74/84 jets, a 6.5 P.V. and 31 squirters.

Something, or things, are holding you back so you need to stay conservative and double-check what you have, mainly in the engine. Can't take for granted that everything was correct when you got it.

I agree with the last statement 100%. There was a lot of stuff that seemed cobbled together. Like the fuel pressure, I mean there was a gauge for it and it was way high. Not sure what the P.O. was doing but I thought maybe he had taken off some 'better' parts before he sold it to me and never bothered to recalibrate. It's all good though, I am grateful for the knowledge that results from wading though this stuff.

 

[70aarcuda]

there are two set of tti headers...straight thru 1 7/8....and then there is the 1 3/4 stepped headers...(1 5/8- 1 3/4 step)

 

[rmchrgr]

Headers are 1 5/8 primary to 1 3/4, not 1 7/8.

The more I think about it, the more I think I should just stick with the W2s, ported or not. Hopefully there is no damage beyond the suspected valve, if that's what the noise ends up being.

Guess I'd probably be going backwards by switching or would at least be closer to the limit with the RHS heads. I can always port the W2s for more power, put a bigger cam or carb in, better converter, more gear and on and on.

Thanks for all the input.`