[71 Ventura II]

Originally Posted by chiphead

Ventura, those are some stout numbers with the 60916 cam. You sure your compression wasn't more than 9.7? My 400 will just break the 12s on motor with the XE274. 3750 race weight. Cranking compression is 165 PSI with the cam adv 2*. 38* total timing. Don't get me wrong, it's fast and fun. But I'm trying to maximize the combo, so I'm wondering if a Crower would work with 9.3 compression.

It seems like the OP has a similar setup, so I'm curious why it's so down on power. I'd love 15" of vacuum at idle. Sounds like this cam really needs to be degreed, to eliminate that as a problem.

Are they checking AFR on the chassis dyno?

Should a 60916 cam be making 15" of idle vacuum at 9:1 compression? I'm at 8-10". Yes, I've got idle fuel.

I'll have to re-verify my "Pre-Porting" compression, I forgot we cut the heads .035 to lower the chambers to +- 71cc down from the actual 77.5/78cc they started at. The 9.70-1 compression was after the .035 was cut off the deck/intake sides of the heads. I also was running TRW L3035F cast pistons with "8" valve reliefs. The pistons are flat without a taper but have +- 12cc reliefs. IIRC my compression started around 9.30-1

My car was lighter than yours with a race weight of +- 3300# Heck that's 450# right there. What gear are you running?

P.S. Using the Wallace compression calculator it shows my original compression was only 9.12-1 and my compression after milling the heads was 9.71-1. My specs are:
bore 4.150
crank 3.75
head 71cc
piston 12cc
gasket .041
deck 0.015 (In the hole)

[Cliff R]

In response to the comment you just made, would you say the factory 744 cam is a good example?

The 744 cam has never gained a big following. A few folks over the years have done OK with it. It has never caught on like the 068 grind. Just to much duration and not enough lift. The engineers came up with the 041 grind, which basically obsoleted the ill-fated 744 camshaft.

I guess at some point you've simply got to add some lift to effectively utilize all that duration. The few experiences I've had with the 744 cam were not positive.

I actually built an ill-fated 428 for my Ventura in the late 1980's, using the 744 cam and #96 heads. It was a TURD, and only stayed between the fenders for a couple of months.

I replaced it with another 428, using 6X-4 heads and HC01a camshaft. Loved that engine, and it stayed in place till 2001 when it was replaced with a 455.

As far as the 60916 cam and advancing/retarding it. We've found it likes to be around 108-109 ICL. A few folks have installed it straight up, which usually puts it aroudn 112-113ICL. The engines didn't respond all that well, and most ended up correctly degreeing it to around 108ICL, where it yielded much better results.....Cliff

[chiphead]

Cliff- What is the biggest cam you'd use in a 400 at 9:1 compression? Assume street port job, forged internals, good machine work. 10" continental converter and 3.55-3.90 gears. Goal is maximize track times and "just" be able to run power brakes.

[1funride]

Ventura. You switched from the 60916, to an SD roller around 230/236. If I recall correctly. How does that compare to the 60916 for overall power band. Seems like it would have much better low end and more overall power....right?

[1funride]

Oops sorry that was hal101 with the SD cam. Anyone have comments on the SD roller 230/236 range. Seems like it would be a strong cam in a 400 with good compression.

[71 Ventura II]

Originally Posted by 1funride

Ventura. You switched from the 60916, to an SD roller around 230/236. If I recall correctly. How does that compare to the 60916 for overall power band. Seems like it would have much better low end and more overall power....right?

Originally Posted by 1funride

Oops sorry that was hal101 with the SD cam. Anyone have comments on the SD roller 230/236 range. Seems like it would be a strong cam in a 400 with good compression.

Your right wasn't me but hal101 and few others tried the HR cams in the smaller
CID engines with great success! I sold the car before I had the chance to try a roller cam. JD

[Cliff R]

"Cliff- What is the biggest cam you'd use in a 400 at 9:1 compression? Assume street port job, forged internals, good machine work. 10" continental converter and 3.55-3.90 gears. Goal is maximize track times and "just" be able to run power brakes."

Can's say as I've ever built a 400 engine at 9 to 1 compression. In the 7.7 to 8.2 CR engines we use the Crower 60240, 210/222/112.

For 9 to 1 a slightly larger 214/224/112 should be a very good choice. The larger 60916 and 60243 cams are going to like at least 10 to 1 compression. I really like the 60243 over the 60916 in 400's with 72 cc heads and manual transmissions, or auto with a 3200-3800rpm converter and at least 3.73 gearing.....Cliff

[BruceWilkie]

Originally Posted by chiphead

Ventura, those are some stout numbers with the 60916 cam. You sure your compression wasn't more than 9.7? My 400 will just break the 12s on motor with the XE274. 3750 race weight. Cranking compression is 165 PSI with the cam adv 2*. 38* total timing. Don't get me wrong, it's fast and fun. But I'm trying to maximize the combo, so I'm wondering if a Crower would work with 9.3 compression.

It seems like the OP has a similar setup, so I'm curious why it's so down on power. I'd love 15" of vacuum at idle. Sounds like this cam really needs to be degreed, to eliminate that as a problem.

Are they checking AFR on the chassis dyno?

Should a 60916 cam be making 15" of idle vacuum at 9:1 compression? I'm at 8-10". Yes, I've got idle fuel.

Debs 406 idles just plus of 15" at 800rpm neutral. About 11.5" in gear idle turned down to 600 (vs the 700 in gear its normally set is just under 13). Compression when assembled was just a tid below 9.7. Cam was degreed and came in at 107.5 with a brand new chain. I'm sure it likely drops back 1/2 to 1 degree by time the motor breaks in. The P65 dual 750 quads seemed to peak in low 5000 rpm range and done by 5500 or so. The RPM 780 combo (no spacer but notched plenum) seems strong to 5500 and levels off till about 6000 then drops notably.

Her convert (T400 2200 stall unknown convertor)with me in it was about 3750 lbs. With the dual quad I got a very best 1/8 mile of 8.05 at @87.5 mph with regular TA 255/60-15 radials and 2.56 gear and 2.21 60 ft. (1st and 2nd gear only). No times on RPM combo but I expect better. Rear currently needs overhaul so not pushin luck till I get the other rear in place(Early Pontiac/Olds 9.3 with 3.08's). I'd say with old intake/carbs 370-390 flywheel hp.