Cascade Crew

blue89 · Posted: Tue Mar 15, 2011 10:45 am Post subject: Go Fast

Hey chevymad, I figured I'd start a thread so I could capture what we discussed at FuddRuckers (btw, the ostrich burger was really good). I'd appreciate your input on what I should do next. I'll look at the pistons tonight and post what I find.

The numbers I pulled from the engine are:
Heads: 353049
Oval port, open 113 or 122cc chamber, 255/119cc ports, 2.08/1.72 Valves
Block: 361959
2 bolt main car/truck
Crank: 3530392
454, cast

I will post the dyno sheet up when I get home. Basically, 245 HP and 360 ft.lbs. to the wheels. Holley 750DP, 71/81 jets, downleg boosters, edelbrock performer RPM air gap intake, and some crappy manifolds. And I did a quick search, the TH400 uses 42hp! Eek!

91RSVert · Posted: Tue Mar 15, 2011 12:16 pm Post subject:

From what little I know about carbs, you should have a 900 on that thing.

I know the exhaust was tricky, but how well do you think it fairs? Any other manifolds off different big blocks that would work better?

blue89 · Posted: Tue Mar 15, 2011 1:03 pm Post subject:

The rule of thumb is 2 cfm per HP. So my 650 was big enough to cover what I pulled on saturday. 245 HP + 42 for transmission means 287 at the flywheel, so 574 cfm.

Twilightoptics · Posted: Tue Mar 15, 2011 2:47 pm Post subject:

650 DP is good for over 350rwhp.

Quasi-Traction · Posted: Tue Mar 15, 2011 4:23 pm Post subject:

I gotta admit, i was still rather suprised, you having the TH400 in there why you didn't go with a vacc secondary carb, though from what you said at dyno, you did get a screaming deal on your DP.

It does make me curious if there's a way to reduce the amount of "popping" in the exhaust on deceleration, or if that's just part of the nature with a mech secondary carb.

Shrug

chevymad · Posted: Tue Mar 15, 2011 4:41 pm Post subject:

I think its rich and igniting the fuel in the exhaust. Any power valves in that carb? Possibly ruptured and sucking fuel out during high vacuum? There was alot of black smoke .. But mostly when you got on it. Alot of that could be from the double pump shot.

Let us know what pistons are in it. That will make a big difference. I wonder if the 113cc version of the heads was used on the 427/402s?

When I was building mine I just bought a cheap hyper piston rebuild kit off ebay to get the compression up. I never did dyno that motor, and honestly even though it sounded nasty I don't think it really put out what I expected either.

For alot of good big block info the chevelle website (team chevelle) is a great place to look. Check out their performance section. Alot of those cars are bb, and the old guys that own them are only barely starting to learn about LS motors..

blue89 · Posted: Tue Mar 15, 2011 8:52 pm Post subject:

It has a single power valve, good condition, 6.5. I just rebuilt that carb a few days before I put it on the trailer. But black soot and running lean? Wouldn't that indicate that I'm still too small on my jets and sucking fuel out when it shouldn't?

The carb was acquired for $50. Thats a screaming deal. I'd love to go vacuum secondary but still haven't found one yet. And if I spend any more money it's going to be towards a fuel injection setup. It is definetly running better with the 750 main body. Maybe I'll toss my 650 main body in it since I already spent all the time cleaning it up and never ran fuel through it. And correct me if I'm wrong, but wouldn't a vacuum secondary only make more power down low as long as the main body is sized right?

Here's my graph.

chevymad · Posted: Tue Mar 15, 2011 8:55 pm Post subject:

Paul any help with this?
Why is his AFR lean when its obviously billowing black smoke?

blue89 · Posted: Tue Mar 15, 2011 9:14 pm Post subject:

PS. I forgot to make sure the car was at operating temp before I went at it. I never turned the fans on and the car was still cold at the end of the pulls. Very frustrated I didn't think to warm the car up, especially with an air gap intake.

91RSVert · Posted: Wed Mar 16, 2011 7:04 am Post subject:

chevymad · Posted: Wed Mar 16, 2011 6:55 pm Post subject:

aaron_sK · Posted: Wed Mar 16, 2011 6:58 pm Post subject:

Does the car have an exhaust leak? That would explain the weird AFR and the backfiring on deceleration.

blue89 · Posted: Thu Mar 17, 2011 8:00 am Post subject:

It may have developed a leak after crushing the pipes getting it on the trailer. I will lift it and check. Also, getting a clear shot of the piston top through the plug hole is trickier than I thought.

RK82 · Posted: Thu Mar 17, 2011 8:01 am Post subject:

http://www.wallaceracing.com/intakecfm.php

91RSVert · Posted: Thu Mar 17, 2011 9:06 am Post subject:

blue89 · Posted: Thu Mar 17, 2011 9:40 am Post subject:

I can see down the spark plug hole just fine if I remove my coolant tank. Oddly enough. Trouble is lighting up the chamber so I can see.

91RSVert · Posted: Thu Mar 17, 2011 4:47 pm Post subject:

I bought a light that is ran off usb power. Its flexible and very small diameter. Just tossing out ideas Smile

chevymad · Posted: Thu Mar 17, 2011 7:38 pm Post subject:

My led maglight works great for that type of thing. Nice pointy bright spot that goes right into a plug hole.

iansane · Posted: Thu Mar 17, 2011 10:02 pm Post subject:

chevymad · Posted: Thu Mar 17, 2011 10:19 pm Post subject:

Naw.. I use the penlight style maglight brand ones for work. They're awesome..

Yours still works great too.. kinda oldschool now with the million led's but still a great light. When it quits I'll give it back to ya.