firestorm

I was looking thru an old GMPP catalog and they show AH rods were included in their ZZ4 conversion kit. I see alot of people recommend the DR, AY and CK rods. Would the AH be the best 350 rod to go with since it was included in the GM kit or are the other choices better? The DR seems the most popular but looks to be the leanest tip on the tech article chart. Thanx

Bunker82

No one can say what will be best without more information about your motor (cam specs, heads, rear gears, etc), even then your best bet is to experiment. If your 350 is close to the ZZ4 then AH would be a good place to start. The only way to find out it to get some rods and try it. And remember richer doesn't always mean better. DR's worked pretty good on my 383, so you never know.

Vader

He's right, you know. Too many variables.

And don't overlook the hanger/cam:

Damon

I have 2 main sets of rods that are my "go-to" starting choices for just about any engine combination you can dream up.

DR rods (or nearly identical CP rods) are fairly middle of the road and a good starting point for most street driven small blocks.

DA rods are richer than the DR rods everywhere and usually work better on bigger cube engines or engines with significantly upgraded breathing (big cam and heads).

If in doubt, go with the richer DA rods. Hang any of them on a "G" hanger and you'll be in the realm of sanity.

Lo-tec

DR rods came stock on my 84 L69. Tad too lean. From my experience CK or CH rods worked best with stock heads (on a 305 or 350) and DA rods worked best with decent heads (dart sportsman). Best way to tell is at the track. You can redrill hangers so they have a high and low hole, but that is super fine tuning. I would also suggest using a G hanger and a collection of secodary rods and keep running it on test and tune night until you figure it out. On my 14 sec turd, going too fat seemed to slow it down by .25 seconds if that helps.

firestorm

Thanks guys. My rebuilt carb came with DA rods on a K hanger. I didnt know DAs were any good. Will give the G hanger a try. Right now I have a cat free exhaust and may add a Performer RPM manifold.

firestorm

With everything fully warmed up I did some testing.

I tried the DA rods with a G hanger and it seems it be loosing power above 3000RPM at WOT. Seems to fall flat on its face.

I swapped in some CK rods and it seemed to run much better above 3000RPM but have very little power below that.

Am I correct in assuming that the DA rods being richer at initial A/V opening then the CKs is why it pulls better at lower RPMs, but is too rich at WOT for a 350 above 3000RPMs?

Fast355

iTrader: (2)

I run DRs (came stock on 1983 full size vans w/305) on a F hanger(came stock on most Olds 307s such as a 1988 cadillac sedan deville brougham). Power everywhere and fuel injection like throttle response.

firestorm

I got some DR rods from the dealer and will try them out. I also have a B, G, I, K hangers to try too.

Vader

Just to verify, you DO have the secondary AV coil spring windup/preload set correctly, right?

84305HO

I like my my combination of B hanger and CK rods

firestorm

I set it following the tech article.

86 sports coupe

are the metering rods in order of lean to rich?

Bunker82

Actually you have it backwards, AD is the richest, and EE is the leanest. The numbers under the degree columns is the diameter of the rod. AD has the smallest diameter (look under the 90 degree column) so inside the fixed jet this will equal a greater area for fuel to pass through resulting in a richer mixture.

86 sports coupe

So I have Da rods ch and cp. Between the cp and ch rods wich rods would be the richer? are the Da rods the richest of my 3 rods? Am I on the right track? also on the hangers, the lowest letter is the richest? an F hanger would be slightly richer than a G hanger? Thanks I just want to be strait. I plan on running a performer rpm q-jet intake and want to learn how to tune the q-jet. Anybody want to recomend a tuning book? I have a haynes but its mostly rebuilding. Sorry this is so long .
Thanks Randy

Lo-tec

HP books Rochester Carbs:

http://www.sdpc2000.com/cart.asp?act...id=518&pid=669

Damon

Yes, the DA rods are the richest of the 3. The CP rods are leaner everywhere than the DAs but are still a good performance rod for a mild 305/350 street motor (they're identical to the DR rods that came in the HO L-69 305's carb). The CH rods are just junky way-too-lean "rebuilder" rods that pop up in lots of QJets that have been around the block.