[Gach]

Thats what I have old G-teck. That vacuum secondary Holly will make it feel like a dog. I’m guessing secondary jetting is off. From what I remember my Buddy with 70 Ram IV Judge, thought it would be faster with that Holly crab. Over the Q’jet it cam with. Long story short I ended up putting a metering block and jetted baby up in the secondaries. His motor was Ram IV 400. He ended up running 12.70’s with it. Stock Ram 1V cam. Yeah with that cam, even if you play with carburetor not going to make much difference.

[Gach]

See whats in that Holley secondaries for jets. You should be around 72’s in the primaries and 76-78’s in secondaries. See whats in there for jetting.

[Gach]

I’m addressing the carburetor because if you end up going with Crower 60619 cam, jetting will still be a issue. From my memory think I ended up with 72’s in front and 76’s in the back. Either way that 2802 cam is a dog, Great Cam for mom station wagon. LOL

[General Z]

Originally Posted by Gach

See whats in that Holley secondaries for jets. You should be around 72’s in the primaries and 76-78’s in secondaries. See whats in there for jetting.

Thanks. I know I jetted up in the front, but think I left the rear alone. I'll have to give it a look.

[Gach]

Definitely do, see whats in back.

[Stan Weiss]

Originally Posted by Gach

Wake that thing up with Crower 60916 cam !! LOL

Gach,
Really? Check the spec on that cam and a Summit 2802.

Stan

[General Z]

Originally Posted by Gach

I’m addressing the carburetor because if you end up going with Crower 60619 cam, jetting will still be a issue. From my memory think I ended up with 72’s in front and 76’s in the back. Either way that 2802 cam is a dog, Great Cam for mom station wagon. LOL

Factory jet is a 72 and I don't think I changed it. I know I didn't change the secondary.

I did however change the accelerator pump nozzle to a .045 Part number 121-145
It came with a .031 nozzle and that was too small.

[General Z]

Originally Posted by Dragncar

I have a extra RPM intake I can part with if interested, used only one season.
.

Sent you a PM. Thanks

[Jay S]

The G tech meter we had provided pretty high mph numbers, but seemed fairly accurate on 1/4 mile times. Not close to as accurate as a draggy.

The 750 Holley’s I have had worked good out of the box in moderate to mildly built 350 to 400 applications. Double pumpers, vac secondaries, didn’t seem to matter. The 750 Holley’s I have done were lean on big engines. One 750 I worked on came off a dyno, and had 430HP on a 383 SBC, we tried it on a 462 with a 60919, ported 96 heads, RPM intake, and HP maniflolds, against a later 800 cfm qjet. I tuned and tuned, and could not run get the 750 Holley to run with the q jet. The 850 holley’s I have had on the other hand, run at least as good as the qjet on 455+ cubes, right out of the box.

If you get into the engine to fix some oil leaks changing cams to something bigger sounds like a great idea. Only worth it though unless the induction can handle the bigger cam. Right now I doubt the induction (carb&intake) would respond much to a cam change with out some tuning.

The current cam Crower sells as 60919 with the 112 LSA would works good in grandma’s 455 station wagon. Definitely not to big.

[chuckies76ta]

The accelerator pump on the carb was changed from the 30cc to the 50cc one. It's the 20-11 kit.

You should not need a 50cc pump on this combo in my opinion.

[Formulas]

Recall anything on shift points ? Could be hanging in gears to long with that first gear ratio and 3.73 it should be zipping through the early gears setting you back hard in your seat with traction

got to keep the engine loaded in its torque range..

[General Z]

Originally Posted by Formulas

Recall anything on shift points ? Could be hanging in gears to long with that first gear ratio and 3.73 it should be zipping through the early gears setting you back hard in your seat with traction

I had found at one point that the valves seemed to be floating a little over 5000 rpm, so I tinkered with the governor on the trans and dialed it in to shift at 5000. While the engine is out, I'm planning to put new springs on, but was probably going to leave the governor alone.

[Formulas]

yeah i think your going to want to shift it quicker, i dont have a dyno seet with that cam in 462 but i bet 500-600 earlier shift point that ET. will drop

[Formulas]

Data point for the future... If your floating valves in a big engine and a smallish cam your going places it shouldn't be RPM wise

[General Z]

Originally Posted by Formulas

yeah i think your going to want to shift it quicker, i dont have a dyno seet with that cam in 462 but i bet 500-600 earlier shift point that ET. will drop

Wow. That's something I never thought about, lowering my shift point to go faster. That would be worth a try and pretty easy to do too. Thanks!

[Gach]

700r4 gear ratio 3.06, 1.63, 1, 0.7, and 2.9

Turbo 400 2.48/1.48.

700r4 Not as good as T-400 that explains some things. Not keeping it in the power band.

[General Z]

Originally Posted by Gach

700r4 gear ratio 3.06, 1.63, 1, 0.7, and 2.9

Turbo 400 2.48/1.48.

700r4 Not as good as T-400 that explains some things.

True, but this is a street cruising convertible that sees plenty of highway use. It'll never see a racetrack.

[Gach]

If the 3.06 is correct its like having to much gear, then thing fades out. Once you hit third gear.

[Gach]

Originally Posted by General Z

True, but this is a street cruising convertible that sees plenty of highway use. It'll never see a racetrack.

I understand, but definitely changes the way car will feel performance wise.

[Stan Weiss]

Originally Posted by SD455DJ

Good memory Jay! Yes, the ’70 YH 455 (+0.040” so a 464) made 390 hp @ 4600 rpm and 512 lbft @ 3400 rpm with the small valve #15 heads (9.94 static compression ratio with 0.040” quench) with the Summit 2802 cam & lifter kit, factory 1.50 stamped rockers & push rods, and factory log exhaust manifolds. It made over 500 lbft of torque from 2800 rpm to 3800 rpm (1000 rpm range). No doubt it was hamstrung with the small cam and log exhaust manifolds, but we were curious what a ’70 small valve 455 would make in the real world with just a cam upgrade. The 2802 is too small and any 10 to 1 compression iron headed 455 needs a 230+ intake duration cam with tight quench and a wider LSA (112+) to manage 93 octane fuels, along with sharp jetting and timing and a good cooling system. Similar engines with this power at the Pure Stock Drags run high 12’s @ 105 mph in a 3900 lb. race weigh A-body with 3.55 – 3.73 gears. This engine was explosive off idle in a ’70 Lemans with an M20 and 3.08 gears. (I found out real quick that the original 3.23 Safe-T-Track 8.2 rear axle couldn’t handle the first full throttle blast!!!)

With the same 464 short block (and 2802 cam) and stock #197 HO heads (8.61 compression with 0.040” quench) and factory exhaust manifolds made a best of 431 hp @ 5000 rpm and 535 lbft @ 3500 rpm. It made over 500 lbft of torque from 2900 rpm to 4400 rpm (1500 rpm range). The cam was pretty good, but the engine could have managed a bigger cam as well. It idled with a little bit more lope than the higher compression heads as expected. It is easier to control detonation and isn’t as fussy from the lower compression but makes more power from the higher flowing heads and exhaust. Similar Pure Stock builds run easy mid 12’s at 108+ mph. The “HO” is just as explosive at a slightly higher rpm, but not much. You really have to be careful when playing around on the streets because you can swap ends before you know it!

There is definitely something amiss in the OP’s 455 as it should be making at least 430 hp and 530 lbft of torque with his combination. I would check the cam install position, timing curve, and fuel calibration and delivery, as it seems there is a lot of horsepower to be found yet without changing anything. Certainly, a factory iron intake and properly built Q-jet (or the 750 Holley) will be better (Q-jet is my preference) than the Performer. Change the cam to one that Cliff recommends is a must for your 9.5 compression and the high piston speed of the 455 stroke. I’d also change the rear gears to 3.08 with the 700R4 trans super low 3.06 first gear, or change out the trans for a TH400 or 4L80 with the 3.73’s.

Sorry for the long post…Dennis

Post #68

If the valves are floating @ 5000 RPM find out why and fix it!!

I am not saying a bigger cam will not make more HP than the Summit 2802, but as shown above the Summit 2802 should make enough HP for you to be running in the 12's.

Stan

Stan