Iron headed 468 on dyno today.
 

Just finished up a 468 with iron 670 heads ported by Dave at SD Performance. Also is running a ported by SD 1967 iron Q-jet intake with a Cliff built Q-Jet. Engine is 9.5:1. Cam is a Lunati Voodoo hydraulic roller with 239°/243° @ .050" duration, ground on a 112° LSA, and just under .600" lift with Comp 1.6:1 ratio steel SB Ford Ultra rockers. Installed 5° advanced on a 107° ICL. Hylift/Johnson hydraulic roller lifters. We ran it first with 4 tube headers on it. Then we are going to install Ram Air restorations H.O. manifold with 2.5" pipe to see the difference between the two. Bore is 4.185", and stroke is 4.250". Block is an early 70's 400 block. 491488 casting, IIRC. It's a street engine, so we ran it on 91 octane pump gas. Here is an average of two pulls. 1 pull from 3500-6000 RPM, and one from 4200 RPM down to 1600 to see what kind of torque it makes down low.

RPM____Torque____H.P.
1600____426______129
1700____437______141
1800____444______152
1900____445______161
2000____456______174
2100____468______187
2200____479______201
2300____488______214
2400____496______226
2500____512______248
2600____---_______---
2700____526______269
2800____536______286
2900____542______300
3000____552______320
3100____---_______---
3200____560______337
3300____566______356
3400____568______368
3500____570______380
3600____573______393
3700____573______404
3800____575______416
3900____571______424
4000____569______434
4100____573______447
4200____567______453
4300____557______456
4400____556______466
4500____551______473
4600____547______479
4700____545______488
4800____540______494
4900____534______499
5000____530______504
5100____523______507
5200____516______511
5300____512______517
5400____508______522
5500____499______522
5600____488______520
5700____472______513
5800____466______514
5900____456______512
6000____419______470

You can see where the lifters pumped up at 6000 RPM, and floated the valves slightly. These are the slow bleed lifters, so they always seem to pump up around 5900-6000 RPM. Built in rev limiter, I suppose. Ought to move a 67 GTO pretty well. I'll post numbers when we dyno with the RA manifolds.

I'll be very interested to see the difference between the headers and RA manifolds.

Wow! Over 500ft lbs torque from 2500 to 5500rpm's, that's getting it done for sure......Cliff

Sweet motor Paul and nice work as always!

Nice!

Nice engine do you mind sharing your valve spring pressures on the seat and open?

Flow #'s of heads?

Very nice combo. Run forever.

Nice Job Paul!
I've had good results with the Voo Doo series myself.
Yes I'd like to see the flow # on the heads as well
Jeff

Excellent build and information Paul, looks like you nailed that one.

Please excuse my very minimal knowledge but what was done to get it to 9.5 cr with 670 heads. Opening up the chambers?

Thanks in advance

Lunati cams are excellent. Butler runs this slightly bigger Voodoo cam in their 600 hp motors. But you made a good choice.

Retro-Fit Hydraulic Roller. Serious street/race cam. Needs 10.5:1 compression and 3200 RPM stall converter. Works with moderate nitrous and small superchargers. Very healthy idle quality.
Advertised Duration (Int/Exh): 294/302
Duration @ .050 (Int/Exh): 243/251
Gross Valve Lift (Int/Exh): .560/.565
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 2600-6600
Includes: Cams Only

150-155 on the seat, and 380-390 open.

I'll try to remember to get the flow sheet today.

Chamber opened up a little, and a custom dished piston.

If I may take a stab at the flow numbers and since Paul has said the Cam was just under .600" lift, I will say 265 Intake cfm@28".
The motor accually only used 253 cfm per cylinder to make that 522 hp.

Pretty damn close Steve! I know it's in the 260's at .600".

Great job, Paul!! I hope the owner has a large budget for rear tires...nice, flat torque curve from 3,000-5,000 with torque output of 540 ft/lbs or higher.

How is idle quality?

The Exh Manifold test will be very interesting as that 4.210" stroke and it's resultant fast pick up of piston speed from BDC wants to pump out a lot of spent gases very early on that Exh stroke!

The 670 castings do not have much Exh port floor which may make them more sensitive to Exh back pressure then other factory castings.