Les

I'm thinking about replacing the old "Turbo" angle plug iron heads on the 355 in my Z28. These heads were leading edge about 20-25 years ago with 2.02/1.60 valves and the angle plugs. They've been pocket ported and have Manley undercut valves in them. The motor is running 11.0 to 1 comp. ratio and an Ultradyne solid flat tappet cam with .503/.518 lift and 248/255 duration @ .050. Headers are 1 3/4" through 2 1/2" exhaust w/ crossover. Carb is a Barry Grant modded 750 DP and intake is a Weiand Stealth.

AFR recommends their 195s and I'm wondering if anybody has made a similar upgrade. I'm looking for any firsthand experience or even any guesstimates as to what gains I might expect and/or what HP & torque numbers this combo would be good for. Thanks.

No Go

Referring to the flow and engine tests that include AFR's...you can't seem to go wrong. I bet you would gain a significant amount. Interesting to do a before and after chassis dyno test. Gain 50 RWHP?
http://www.chevyhiperformance.com has compared a ton of heads on same flow bench for reference.

With 355, some might say they are little too big. Maybe 190's? On the other hand, you cam says it is pretty roudy so why not. I'm pretty sure I'm going with 210's for my 406.

:)

Les

No Go,
Thanks for the link. The car in question has actually been in CHP- only in the Reader's Ride section though, so not a big deal. Car Craft just published a build up of a 383 w/ the AFR 195s w/ slightly more cam than I have and, w/ some tuning, pulled 540 HP. The same heads on a 350 w/ a wicked roller cam pulled 520 HP. I know that's well above what I could expect but it does show the potential of these heads.

Your idea of running dyno tests to compare before & after would be very educational....something to consider for sure.

The right cam in your 406 w/ the 210s would kick butt! I'm pretty sure you'll have to change your username though. :yesnod:

jerryjfunk

I'm building a 383 and am using the 195's. We were considering the 210's but realized that they would be a little big for street use. Maybe you could consider the 190's, but based on that 520hp figure, the 195's sound sweet! By the way, what was the 540hp 383's compression ratio? I'm looking at 10.5:1 for mine.

Jerry

Les

Jerry,
Their comp. ratio was 10.5 to 1 also. They used Probe pistons(Part #P3831F), a Holley HP 750(Part #0-80528-1), a Victor Jr. intake, and the Comp Cams Magnum 294 solid cam(Part#12-224-4). Torque curve was fat, peaking at 517 lb-ft at approx. 4500 rpms. Good luck w/ yours- I'm sure it'll be potent!

No Go

Well the 406 is going in my NOVA so...

:)

gkull

Les - how does the car run now? I ran a milder duration than you sollid roller in my old 355 with P&P double humps 2.02/1.60 with 10.7 flat tops and I really had to work on the ignition curve to stay out of detonation with 93 octane. I then moved up to Dart Iron Eagle 230cc P&P 2.055/1.6 and the motor was a screamer till it blew.

I'm a Dart aluminum head man now. The way I look at it buy the best first and that way a couple of years down the road when you go up in ci or something you don't have to go get new heads. My mistake was not going with altered valve angle and spread port exhaust.

I have found that you can make very street friendly motors with less cam and big flowing heads. Your cam with big overlap will get pretty lazy down low with big cc heads


[Modified by gkull, 12:49 PM 6/27/2002]

Les

gkull,
I've been on the run or I would have responded sooner. The motor actually runs great now. I'm running about 16 degrees initial timing w/ a total of 38 on a fairly quick curve. It will run on pump gas but it obviously wants more octane. I use a lead additive as insurance & to get the most out of it.

I had Ultradyne use profiles from 2 different cams to get as much cam as I could and still run enough vacuum for power brakes. I wanted plenty of duration to keep cylinder pressure down a bit w/ my 11:1 pistons and it seems to work well. That was many years ago but I just checked out their website recently and noticed that they now have my "custom" cam in their catalog.

I figure that the aluminum heads should help w/ octane requirements in addition to the obvious flow advantage. You make a good point regarding my overlap combined w/ high cc heads, but I'm really not worried because the car has 4.10 gears and pulls real strong right off idle. As soon as I stab the throttle in 1st gear the tires break loose as it is, so even if I lose just a touch of bottom end I may actually go quicker.

It sound like you're a Dart guy. I've heard great things about them and will take a look at their line too. I definitely want heads that are ready to bolt on right out of the box.

gkull

Les - these are what I'm basically running
http://www.dartheads.com/sbpro227.htm Only I have titanium intake valves and because I was thinking about using NO2 I had Dart intall 1.625 exhaust valves. In retrospect I should have went with 2.10/1.6.

I have a set of 292 casting iron angle plugs like yours also 2.055/1.6

If your fine with iron and that compression I would go higher with aluminum. The darts have high swirl fast burn technology so you only need to run @ 32 degrees of max advance to make the most power.

Smitty's75

No Go,,I went with the Dart 230's, for anything 406+ I like their spec's better (2.08I 1.6E with .550 springs),,out of the box they were better than the 195's WITHOUT any port work.

StingrayRacing

I'm running fully ported 210's with a solid roller 383...the car is very very strettable and make plenty of low end tq...like the time i was at the track and my 2-3 shift turned into a 2-5 shift...ran 11.77 (with slicks) thats torque.

Like Gkull said, plan ahead...you know this power stuff is addicting and it seems like you never have enough hp (i.e. Monty!)

Call AFR give them your motor specs and see what they recommend for your application.

gkull

Monty also ran AFR 210's after being dissatisfied with 190 or 195 on his 383


[Modified by gkull, 3:04 PM 7/2/2002]

h rocks

I've got the full CNC'd AFR 195's on my Superram motor. Just breaking it in, so no dyno info yet. I can tell you that we had them flowed locally to verify the AFR #'s, and they were dead on. My engine builder had them compared to a known set of Dart 210's that were heavily worked. He commented that at .400 they flowed 251 cfm and over 284 at .500". He said until ~ .550 lift this set of 195's flowed better than that set of Darts. They also used the air probes to run some velocity tests and he said that they were "awesome", and again was very impressed when compared against the bigger, massaged Dart heads. I don't have the velocity numbers, or I would post them. The guy that made the comments has used Darts almost exclusively on Chevy motors for years, and is never quick to offer favorable comments on "competively" built heads. Take that FWIW. I'll try to get the velocity #'s next week. The thing does have some serious low end TQ even with a "big" 233/240 .578 IN 1.6 / .550" EX 1.5 hyd. roller cam. (for a SR/TPI setup) My guess is that with a carb, you could definitely get a lot more using the bigger 210's without any problem.

Les

Good info from all- thanks.

h rocks,
Really interesting stuff...FWIW, the AFR tech told me I'd pick up another 20-30 ponies if I stepped up to 1.6 roller rockers. That'd put my lift right about at the .550 mark that you mentioned. I'll be looking forward to any velocity numbers you can come up with. :cheers: