I just finished a set of small block Indy T/A heads, or Indybrocks, whatever you want to call them. This was not a typical porting job, but a very extreme one, and the casting was taken to its limits. I haven´t seen too many flow results of these heads so I thought I´ll share mine.





Beside porting and seat work the only modification was bigger intake valves. Port volume is 220cc. Minimum CSA is 2,70 at the push rod, and throat CSA is 2.75 . Port entry dimensions are 2.40” x 1.18”, and entry CSA is 2.76. Average air speed at the pushrod was 280fps, and highest local air speed was 380fps at the middle of sst apex. Air speed was measured at .550” lift/312cfm flow. At .600” lift air speed was 8fps higher.

And now some pictures.

You port work looks great!

Yay! Real tech info!

good heads that make good power for the money. nice job

they are a good head that works well mine flowed 317 with a 2.055 valve and they went every bit of 650hp on a 416

This is an old topic, but I never updated the rest of the engine combo or the dyno/track results, so here we go. Better late than never.

Engine specs:
X-block, half fill, 4-bolt mains
4.080" bore, 4" stroke, 6.250" sbc rods
12.6:1 custom pistons
mech flat tappet cam 272/276@.050", .611/.627" lift, 106lsa
M1 tunnelram, Q-750-E85CT carbs
1 7/8" hedman husler headers

It made 641hp@6600 and 561ft/lb@5000 on the dyno. The cam is definitely holding back the power, and the compression is pretty mild too, but on the other hand this is a street car engine, not an all out race engine.





This engine is now in my street Duster, 3370lbs, footbrake, 727, S60. Best ET 10.41 / 129.77mph





And heres the car in action, a video of a trip to a racetrack.
https://www.youtube.com/watch?v=vEL7I71V6h4

I see 761 tq...................

The dyno sheet is wrong. Looks like it is off by 200 ft-lbs which is probably why he said 561.

Thumper and andyf that's 761 newton meters which equals 561 ft lbs.

WOW my sons .040 over stock crank 360 that has gone 10.50's at 3150 pounds with a 520 lift cam and Edelbrock heads must make a few more HP than I figured.

I like the MPH. Almost 130 at 3370 is making some steam( if thats right) I went 129+ with a 260@50 flat tappet and W5 heads on my cast crank 416 one summer before the crank broke( 727 tranny, 3350 weight) but it wasn't more than maybe 600 horse to do that.... Maybe. Tti headers and a 4150 carb, about 11.5 compression.
I don't know around here if I would call a tunnel ram, 12.6 compression, and a huge 272@50 cam street able...... But, you guys have bad weather 9 months a year over there, and cold/ cool weather the other 3 months, short season, so I guess anything is street able...... Lol

Gotcha................

You should try a cam with less duration and more lift. I think you'll pick up both torque and power.

Someone always has to pee in someone elses cerial.

Perhaps the rest of the combo is not sorted out yet as well as your sons. He does have more weight and is still faster. May need to work on shift points, gearing, converter, maybe his fuel system need some work... a million things can change from dyno to track, dyno is just a fun tool but a valuable tool no less. I know you don't race a dyno but there is a lot more to what happens on the track than just a HP number.

For what it's worth I think ANdyF is right about the cam.

I know it needs more lift, and I´m going to replace the 1.5 rockers with 1.6 ratio rockers to help it out a bit. I dont want a roller or higher CR because it would make it less streetable. It also needs shorter gears but I´m not gonna do it for the same reason, a lot of compromises because I drive it on the street. I drive it also to the race tracks and it has been trouble-free.

I must also say that I have only 4 passes with this engine on a proper race track, those are the ones in the video I posted. And I did not make any tuning at the track. I mostly race on airfield tracks with no track preparation.

I'd recommend a copy of PipeMax to help with the cam selection. You have head flow data and dyno data so PipeMax should be able to add the next level of information. I'm thinking you could reduce your cam duration by 20 degrees and have a better overall combination.

Post your combo over on SpeedTalk and ask for a cam recommendation. I bet that Mike Jones tells you something in the 250 range with 650+ lift. But who knows, sometimes he surprises me.

I do have pipemax and I know somethig about selecting a cam myself too. The cam is not optimal for racing or for street driving, but again, its a compromise engine.

Why do you think the cam has too much duration for this combination? Is it the compression? Did you look at the head specs? I dont match cams for compression, I match them for heads, and then I match the compression for the cam. This engine has relatively low compression, but its like that on purpose, because its a street car. The combination may look off to you,but its my way of doing it.

These heads would carry the hp up to 7000 but the cam is holding it down, the valve does not open enough. 1.6 rockers will help some, and I´m hoping to get the hp 100-200rpm higher. Next time the motor is out from the car I may also retard the cam a couple of degees and raise the CR a little. If I can get the hp up to 7000rpm the intake would be tuned too.