gwarren007

iTrader: (1)

I know Chevrolet Performance and Comp Cams were having issues with their roller lifters, who is the go to currently? I have a engine that's not for a F-Body, but I value your input.

This is for my 1978 C10 (for now).

Smeding performance 383 short block
Mercruiser 94666492 camshaft
Cloyes timing set c-3064k
Summit racing 67cc Vortec head
Chevrolet Performance head gasket (.028) - 14096405
Factory roller spider and dog bones
I have a 1800 stall speed TC and 3.42 LSD.

Buccaneer

I use nothing but Morel roller lifters in my motors, I love them.

84 4+3

Morel is good. I have a set of howards that are made by morel that are a little noisy when cold but otherwise have no issues with them. Summit HT217 are the morel 7717 lifters that most people use in stock roller blocks and are IMO what I would use. The 7717 is no longer a full polished lifter but has the better internal valving.

Schurkey

Is that a step-nose roller cam? Do you have the proper thrust plate and bolts to keep it from walking forward?

Is that timing set suitable for a step-nose cam?

gwarren007

iTrader: (1)

Its a step nose cam. Its a timing set for F-body/B-body and pickup trucks from 87-2003 (305 and 350).

I have a new hold down with thrust plate.

Schurkey

That's why I asked...most TBI pickups had flat-tappet cams. I don't know which carlines got flat-tappets vs. hydraulic rollers. The service-replacement crate engine I bought in '99-ish was intended for a '91 Caprice. Had a roller cam, but a single-roller timing set, not a "silent" chain.

As long as the cam gear fits the cam, you're set.

Fast355

iTrader: (2)

One suggestion, ditch that chain set for a Cloyes 91157. It is a single roller that is a stronger and more durable chain. The 91157 is equivalent to the stock GM Marine, HD L31 and ZZ4 chain set. Most 383 rotating assemblies will not make a full revolution without smacking into the camshaft if it is not timed correctly. The last thing you want is a broken inferior chain grenading the engine.

gwarren007

iTrader: (1)

Will do Fast355

Fast355

iTrader: (2)

On other thing I forgot to mention. Loctite the cam bolts.

84 4+3

I get a locking plate generally too. Can never be too careful if you're putting in the time.

skinny z

https://www.johnsonlifters.com/

USA made. You get what you pay for.
​​I see too that Morels are made in the US.
​​​There's not a chance in hell that I'd put an offshore valve train component in my engine. (Not that anyone has suggested that here...).

gwarren007

iTrader: (1)

So this cam doesn't have a fuel pump lobe for a mechanical fuel pump. So a 151 cam or a 08-411-8 camshaft?

Fast355

iTrader: (2)

08-417-8 has a very flat torque curve with Vortec heads. I have used it in both a boat and a Suburban. 151 works well in a 350 had one in my Express van, never used one in a 383. The 151 will work best with a S10 converter that stalls about ~2,800 behind a 350.

Fast355

iTrader: (2)

Have you calculated your static compression ratio? Is this a 5.7" rod? 3.75 or 3.80" stroke.

gwarren007

iTrader: (1)

3.8, 4.0155 bore 13.5cc dish pistons .0155 in the hole 67cc summit heads 4.100 gasket .028 thickness

Fast355

iTrader: (2)

I looked at the Smeding 383 specs. 4.00" bore x 3.80 stroke, 13.5cc dish. I came up with 9.72:1. The flow numbers for the Dart/Summit Vortecs are nearly impossible to find other than they max out at 232 cfm @ 0.500 intake and 138 @ 0.500 exhaust. I modeled it with a performer style dual plane, a 650cfm 4bbl, 1-5/8" primary long tubes and decent exhaust. With iron heads and pump gas, I feel the GM 151 and 08-410-8 will both have too much dynamic compression to run well on pump gas.

With the 08-417-8 DD2003 predicts the following
RPM--------HP------TQ
2,000------166------436
2,500------212------444
3,000------255------447
3,500------302------453
4,000------343------450
4,500------371------433
5,000------374------392
5,500------356------340

gwarren007

iTrader: (1)

Thank you. I knew I would be on the edge.

Fast355

iTrader: (2)

I crunched the numbers on the 260HR, the XM270HR as well as a 3rd cam.
The 3rd cam is the Lunati Bare Bones LT4 hotcam, 20080130.
It is a 276/286 @ 0.006, 218/228 @ 0.050, .503 lift, 112 LSA and 108 ICL.

The 260HR is 8.30 DCR
The XM270HR is 7.92 DCR
The Lunati is 7.78 DRC

At 2,000 rpm the Lunati is down 10 ticks, but it comes back strong in the midrange compared to the XM270HR with 385 hp at 5,000. At 3,000 they make the same torque. At 3,500 the Lunati pulls ahead 10 ft/lbs and stays there. IMO the Lunati would be the most octane friendly. The XM270HR should be able to be tuned on pump gas with the tight quench. The 260HR just has too much dynamic for iron heads on pump gas in a heavy truck. Generally speaking 8:1 is the limit for iron heads on pump gas.

I have setup and tuned that Lunati in an OBS Yukon on 37s. It was a stock L31 bored 0.030" with flat top pistons and headers. With a ~2,000 rpm converter and 5.13 gears it would roast the 37s off it. I would have no reservations running it in a 383 with over 9.5:1 compression.