20 replies to this topic

[Orleans]

Have two manifolds: KC 253 308 and GM 88-2. Would one be better than the other?

[fuzzypumper]

Have two manifolds: KC 253 308 and GM 88-2. Would one be better than the other?

Performance wise I doubt they would be any different, quality wise I cant speak from expirience but my friend has a KC one on
his Commodore it seems Ok. It was designed to be an aftermarket stock replacement.
If I'm not mistaken one advantage of the KC manifold is it has the dual carby bolt pattern so you can
put a quaddy or a holley on, versatile.

[yel327]

The KC manifold is a copy of the VH/VK GroupIII manifold but it has ribs in the plenum floor whereas the HDT one is smooth. The KC has the advantage of fitting on all pre EFI heads. If the 88-2 you have is a GroupIII manifold use it, if it's just a stock blue/black use the KC. An Edelbrock Performer or a stock HT-HJ/LH manifold on early red heads would be better than the KC though.

[makka]

the castings on the KC are SHIT! 1 came on a 253 I had and I spent ages fixing it up, the ports were all different shapes and the finish inside the plenum was rubbish. as Yel said, if you have pre poll heads go with the early standard manifold modified ala L34 or a Performer, performers also fit blue and black heads but are "illegal" on pollution engines

[makka]

the performer does not have an egr valve, it has the crossover but no valve which makes it illegeal to use on any holden V8 post 1975 so that includes some red and all blue and black

[yel327]

the performer does not have an egr valve, it has the crossover but no valve which makes it illegeal to use on any holden V8 post 1975 so that includes some red and all blue and black

Not quite true. ADR27A and even later V8 manuals didn't have an EGR valve, they had a plate blocking off where it would have gone. They still had transmission and temperature controlled spark advance but that can be fitted to a Performer.

[yel327]

Early manifolds are good because GMH Engineers got it right, and stuffed it all up with ADR27A mods. The early manifolds are almost as good as an Edelbrock Performer. When I locate the Dyno proof i'll post it up. I'd be surprised if a stock KC manifold out-flowed an original VH/VK Brock, especially with that awful ribbing in the plenum. Happy to be proven wrong though.

No manual V8 HX-VK should have an EGR valve, since the Performer has the exhaust crossover it should be legal on a manual car.

[yel327]

Just have to find it. I thought I'd found it the other day but it was the Cleveland article. I have to post it up on AussieV8's so I've been looking for it for the last few weeks on and off.

[Redslur]

Good choice of manifold in my experience. There are better ones out there for more top end / higher rev performance but for a nice streeter I would have one any day.

[76lxhatch]

I have a Performer at present on big valve Yella Terra style heads using a modified Quadrajet, haven't had any hassles with it at all. It doesn't have the exhaust crossover though, just sets of holes for all configurations if you have exhaust ports in the heads it just blocks them, but I can't see how that would be an issue for legalities because the crossover itself isn't an anti-pollution measure.

[76lxhatch]

No I was talking about the exhaust crossover in the middle which came in around HX(?) and then changed style around the intro of the blue motor I think. Its basically used as a replacement for the manifold water heater in earlier models, and supplies the EGR (where fitted) as well as the original heated choke mechanism. You will see that a new manifold has three half-drilled holes in the middle either side, you finish drilling whichever ones suit your heads depending on the exhaust crossover configuration or lack thereof.

Unless you have one of the uncommon Holley bolt patterns, which I doubt, a Performer will accommodate it.

[Struggler]

I love the Performer for street driven applications.

About 15 years ago I engine dynoed a 326ci 308 with B Cast heads and a small solid cam. I swapped between a Performer, a Torker and a Stripmaster. The Performer with a 2" spacer made the most torque, the Torker was the worst (never matched the Performer and was up to 25 ftlb down in the midrange). The Stripmaster did make more power but didn't pass the Performer until after 6000 rpm. And yes, I tried a heap of spacer combinations with each intake. Even today few people believe the Performer is better than the Torker. In fact Craig Bennett recently did a similar test with his own intake and the Performer still beat the Torker everywhere.

More recently a friend dynoed his 355/308 with a Performer and 2" spacer (ported heads and Crane 300A). He then fitted the new TP single plane hi-rise intake and re-dynoed it. Same as the Stripmaster, it picked up from 6000 rpm on and held on for an extra 400 rpm. On the street he maintains the Performer was better.