skinny z

Mellings measure their advertised at .004" don't they? GM too?
That's about 7 degrees in the difference when comparing to somebody likes COMPs measurement of .006". Both at the lifter.
So apples to apples it's more like 254/269 . Really gentle on parts by the looks of it.
Or is that math off a bit? Less spread with a small cam?
If it's right, that would be a snappy spec. Premium fuel but really good torque. And that's at 9.3:1. (Yes, you could tune it for regular fuel.)

That's very close to Mortorq's spec. If you slot it into the posted spreadsheet it basically overlaps his custom cam. The difference wouldn't be observable.

F-BIRD'88

Yes and yes..

If its a mild short duration cam he wants this one is proven.... Its also used in the popular GMPP 383HT crate engine with vortec heads.

The Melling 22280 cam in on 104 will work fine with 9.30:1 cr.. Its just better when the CR is 10:1 and on that engine is not hard to get there.
It will be a great performer in this car.

I'd run either of these cams in that 305 with 10:1 cr.
I'm doing a similar 87 flat top 305 roller engine (stock short block) using full ported modded GM "081" heads. Melling #22280 (104/116) 1.6/1.5 rocker set
Th2004r stock converter 4:10's Weiand 8126 QJet
Mid length headers 2.50" dual ex w.cats
10:1 cr. I have no fear using the .015" steel shim head gaskets on it. Never had one fail in 40 years even with 12.65:1 cr. (race gas)

The ported "059" 305 vortec heads are interesting.
I'd CC them to verify chamber volume.
They don't look like 58 CC to me.
You want 56 cc for 10:1

Mortorq

If I didn’t wait, & went with Fbird’s Melling 22221 or the GM 395 cam, I would like to get closer to .500” lift to truly take advantage of the little Vortec 520 heads better flow.
Then there’s that base ZZ4 cam too 🙄
Have not found self aligning 1.6 rockers though, stamped or rollers. Maybe my google machine skills are lacking. Really appreciate the help here.
Dyno’s Marlin Perkins comment was an actual lol.

F-BIRD'88

Elgin. has 1.6 sbc self guide long slot stamped steel rockers.

Mortorq

Fbird88- Thanks for that Elgin tip!

skinny z

The Melling catalogue shows the 22221 as a 110 LSA. (Not that it matters all that much).

Fast355

iTrader: (2)

For me that cam is too small for what I would want. Its done making power around 4,500. I also feel the 205 @ 0.050 would be too small for me. The 305 still has a 3.48" stroke and the small bores need some cam to move airflow through them. When I want to pass on a two lane road, I want to be able to drop a gear or two and get up and go.

skinny z

It IS small to be sure but would undoubtedly have good torque at lower RPMs. That said, it could well run out of steam at the top.

My personal choice, but not necessarily by a clear margin, is still the COMP 270HR. It looks to be a good balance duration wise, has decent lift with 1.5 rockers and with a 9.3:1 compression ratio, might very well work with regular fuel.

skinny z

There are 3 part numbers in stock at Summit.

https://www.summitracing.com/search/...ss-steel_steel

Fast355

iTrader: (2)

Still what I would run myself too. Good balanced average power and decent idle manners.

I am playing with rocker ratios on my 383 currently. Running 1.7 intake and 1.5 exhaust currently. Tamed out the engine a bit and it now makes more low-speed torque without losing top-end. Cam specs are a bit goofy now.

270/284 @ 0.006, 218/224 @ 0.006, 0.578/0.500 lift. When the Rhoads lifters are bled down as in static neasurement. 250/264 @ 0.06, 198/204 @ 0.050, 0.558/0.480 lift. Had to change the radiator yesterday evening and caught a clip of it idling. That was idling with the ac on.

Mortorq

Thanks for the rocker arm info skinny.

I should get the half-inch drill and open up the push ride holes in the head a little, correct?

The lift could be bumped if I didn’t end up with the magnum 215

What do you think of those previously listed guided stamped 1.6 Elgin rocker arms that Fbird found?

Don’t mean to be a tightwad lol, didn’t really want to throw a whole extra amount of money into this basic 305.
cam.

skinny z

Budget understood.

Regarding the Elgin rockers: All I could find were stamped steel. Plenty of circle track engines with these as the rules permit only that in some cases. That said, I'm in the full roller camp. Reduced friction aside, a full roller makes setting up the geometry much easier. At least for me it does. I'm somewhat **** about that as I've had too many valve guides gone way too early when I didn't pay really close attention. It's not so bad with a cast iron guide (as in the GM casting) as they're very durable but once you get to bronze guides, that durability suffers if things aren't set up correctly.
The move to a 1.6 ratio would mean opening up the pushrod holes. Seeing as the heads were designed with the self guided rockers so the holes aren't the guides, there may not be much to clearance but I did my first set of Vortecs just the same.

On the subject of budget, it's difficult to source pricing and product availability as it seems to be all over the map. But using Summit as guide, COMP 270HR in stock at $400. Melling 22221 not in stock but still priced at $400. Melling 22280 at $282 is a special order. GM 395 is $260 and currently available.
As you mentioned, the 395 would benefit from a 1.6 rocker. The PRW 1.6 roller tips were something like 150 bucks.

The one thing that bugs me about the GM cam is the advertised duration. Has it been covered where that spec comes from? (Probably but I can be forgetful at times). As in what lift point? It must be zero I would think as compared to .004" for Melling and .006" for COMP. And even with 1.6 rockers, it's still a little lame on the intake lift.

skinny z

Very smooth.
How are you liking the 1.7 ratio? I've WAY too much invested in my rocker arms to change and here's hoping the new cam won't necesitate that however the idea of a higher ratio than the usual 1.6 I always figured was outside of what's workable. But evidently not. And I've read of others doing the same.

Fast355

iTrader: (2)

My friend David Kauffung has 1.8s on the intake of his GM Fastburns on his former Engine Masters 305 entry.

1.7s were working great, just the 10° duration split on the cam was blowing low-speed torque out of the tail pipe.

vorteciroc

I really wish that there would be a complete Shift in which the way Camshafts/ Valve-Train Sets are Categorized, Marketed, and Selected.
...Throw away groupings based on the Advertised Duration and Lift Specifications as they have been all these years.

I would rather have Camshafts First selected by the desired Behavior, Power Target, and a 360* Degree Plot of Corresponding Valve-Events that produce the desired Behavior and Power...

Use IV and EV Open and Close Points Plotted on two types of Graph/ Diagram, instead of just tossing-out an Advertised Duration via a given Lobe Measurement.
With the Plotted diagrams:

Intake and Exhaust Lift can be selected from Cylinder-Head Flow Data/ Efficiency and the desired Engine Behavior
(No need for 0.730" Lift on something like a Variant of a Vortec-350 Head that Flows NADA above 0.550" Lift).

So, the Camshaft should List the Four Valve Events (Shown Plotted)...
Then the LSA and the Lobe Centers (Shown Plotted)...
Then the Valve Lift.

...and if really desired, the Current Listing Method LASTLY.

Fast355

iTrader: (2)

On the subject of me cheating a bit on DCR for pump gas and getting away with it. I think this might have a bit to do with it. Running a big clutch fan and good size radiator. This was taken in 95°F after idling with the ac on for over an hour. Fan and water pump is 33% under driven. Running down the road even towing a trailer it runs at the 1/4 hash mark on the OEM gauge. 170°F stat and the PCM reading shows 176-182°F. It was showing 185°F at idle, which the IR gun pointed on the thermostat housing right next to the PCM sender closely agrees with. Sending unit for the OE gauge is in the driver head between the #1 and #3 header tubes. I also run semi truck coolant that has added additives for heat dispersion that helps prevent localized hot spots (thus detonation) and water pump lubrication as well as protects aluminum and cast iron well.




i also take a bit of time and work to get all the trapped air out of the cooling system. I see alot of overheating issues from vehicle owners that will fill a radiator, run the engine until the thermostat opens, then top it off, shut the cap and they are done. After 30 minutes of idling my cooling system was still purging air. After 1 hour of running it was pretty much filled. The amount of air coming out almost had me concerned that I had a head gasket leaking. Block gas test said no to that though. I always jack the front end up and place the vehicle on jack stands.

30 minutes in you can still see the air bubbling up through funnels the neck.

BadSS

The GM 94666492/Crane 2032 copy is within 4.5 HP and 2.5 lb/ft TQ on average of the Comp 270 via DD2000’s estimates. I ran them through EA Plus to see what it estimated before making this post. While the numbers aren’t the same, the average results of the “GM492” came within 3 HP and 2 lb/ft TQ average of the Comp 270. Plus, although the Comp wouldn’t be problematic, the GM492/Crane would have about an inch more vacuum at idle.

I even simulated the 207/213-112 measured results someone made of the GM492 and compared it to the Crane 2023 specs - just in case it really isn’t an exact copy. Average TQ and HP from 1750-6250 were more or less equal with the 214/220-112 specs making 1 to 3 more HP over 4250rpm and the 207/213-112 specs making 1 to 3 lb/ft more under 3250rpm.

It appears the 492 cam is available at worldpartsdirect.com based on them saying they have 2 available on eBay at $155.40 shipped.
https://www.ebay.com/itm/40363541738...kAAOSwmNJib-6z

Since they should have two in stock, might want to check directly with them and see what the shipping would be to you - it's showing $108 and $20 shipping to me ($128). https://www.worldpartsdirect.com/oem...shaft-94666492

I also wouldn’t hesitate a second running the Elgin 1.6 stamped steel rocker arms on the GM492 cam either.
https://www.competitionproducts.com/...tinfo/ELG6738/

While it’s been a quite a few years, I’ve used those ($110 - hopefully still made in the USA??) and the Crane stamped steel rockers a number of times without issues on hydraulic cams around and under .500 lift. That would be another plus for me to go with the GM492 cam - $238 shipped for the cam and rockers.

skinny z

All true although I think the inclusion of the requisite amount of overlap for the application is equally as important. I think this would be the "desired behaviour" aspect of your description.
Duration can be the result of determining that and the LSA.

One set of principles I like to follow, whether right or wrong is open to debate as is anything, is to define a cam spec as follows: Overlap, LCA, ICL and how it affects all four valve events, lift and duration. Notice how duration is last.

It seems very few consider the overlap when trying to determine what will work and what won't. The trend I see is that when the amount of time the intake and exhaust are open at the same time (using seat to seat timing or IVO to EVC) and the LSA for the engine spec (related to intake port flow, cubic inches and compression ratio) is determined first, the duration values for what one has come to expect are very much reduced. This is not to dismiss duration as being important. It's especially useful when comparing a group of lobe profiles. The duration at a given lift (.006, .050, .200 etc) gives a better insight into that lobes intensity. This in turn will help decide how aggressive you want to get. A decision coming my way in the near future.
It all relates to how much torque can be produced from that engine package. The HP comes from the RPM and that engine package has to be capable of supplying and evacuating enough volume to achieve the RPM and HP target.

These are things that are NA SBC as this is where my interest lies. I don't build DOHC fourbangers, Pro Stock engines or anything forced induction. Those are different animals altogether.

skinny z

Cooling is paramount. Both for engine temps and inlet air temperature.
If either is lacking, then any marginal pump gas engine is doomed.

DynoDave43

iTrader: (11)

I'm glad my bit of "Marlin" humor was not lost on you all. You need to be of a certain age...And I'm joking about waiting to see what others do of course. Getting my garage assembled after last years fire, and unexpected home repairs have derailed all of my T/A plans for this and next year. That doesn't stop my from continuing to acquire parts and make plans.

Thanks for the additional detail on the Crane 2032 BadSS.

Fast355

iTrader: (2)

Oh come on Skinny! DOHCs are fun. I have a 3.5L V6 DOHC that has 220K miles on it and has never been opened up beyond a valve cover gasket replacement. Through a 5spd Auto it makes 318 RWHP and 282 RWTQ. 28 mpg highway crusing along at nearly 3,000 rpm @ 75 mph with the factory gearing. It has air intakes, headers, high flow cats, 2.5" dual x-pipe equipped exhaust and tune. It has cams that measure 200° @ 0.050 and 0.380ish lift. It makes peak hp at 7,600 and peak torque at 4,300. The intake cams advance up to 45° degrees from the intake centerline and the exhaust cams retard up to 30° from centerline. 3,400 lbs 4 door sedan has run mid 12s at 108 mph on street rubber with over 200K on it, drove it to the track with the ac on and drove it home the same way.

skinny z

I can appreciate all of that Fast. There's something to be said for four valves per cylinder and variable valve timing. If the SBC was that way, we wouldn't be having discussions about overlap and intake centreline.
But the SBC is at the core for me. It's what I started wrenching on when I serviced the family station wagon as a young teenager in high school. A 307 in the brand new 72 Chevelle wagon. Then my first car, a 68 Beaumont (Canadian Chevelle) was another 307. Then fuelie heads, headers, intake and Holley carb followed. And that morphed into a 400 SBC all built in my tech college days. I terrorized a lot of the streets when the street racing stigma wasn't so strong. But it would be another 20 years before I was hot rodding again. And right back to the good old SBC.
Long live the pushrod V8! Despite it's archaicness and lack of sophistication.
I just dig the V8 sound.

Fast355

iTrader: (2)

I know what you mean. I have been wrenching on them since the early 90s helping my dad work on the old G20 and the C10 he had. I remember having to change a valve cover gasket on the 83 G20 in a camping area of a state park after it started puking oil. I did my first top end rebuild at 16. My mom was shocked and amazed when it fired up.

Might look a bit off with all the OBD2 Vortec stuff all over it, but it still has a SBC heart.

vorteciroc

I'm just curious...

What did the Newer-Design Lifter Trays cost compared to the Steel "Dog-Bones" (Better IMO)?