Cam specs???

[shag766]

ok guys here is the spec's for the cam in my hemi.
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lift int. .507
ext. .491
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duration at 050 is 238*
advance duration 286*
centerline is 105*
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installed at 105.5* 1/2* retarded

Racer Brown grind #ssh-25 hydraulic

when we started it up last week it didn't seem to have much of a lump to it. pistons in it are Keith Black KB 210
just curious. rick

 

[lewtot184]

the old ssh25 that i remember had some lump to it. the kb210 piston is lower compression than stock. lower compression will tone down the lope.

 

[70rr-brian]

Correct me if I am wrong but the stock 426 hemi cam specs were not much less than what you put in it?

.467" Int, .473" Exh (1966-1969)
.490" Int, .481" Exh (1970-1971)

276 deg (1966-1967)
284 deg (1968-1971)

Just doesn't seem like a big enough change to be terribly noticable to the ear. Or at least I wouldn't think so.

 

[lewtot184]

the 68-71 cams were [email protected] and 112lsa. if i remember correctly, the ssh25 has a 108lsa and racer brown had a different twist on advertised duration. the ssh25 may have 20 degrees more overlap at .050; significant difference. there may be some tune up issues here.

 

[shag766]

it was re/built as is when i bought it. we didn't run for long and at a higher idle, 900-1100. first time run in 7 years. carb needs adjustment for this engine, 850 holley of my b/b chev. thanks guys. rick

 

[383man]

Thats really not alot of cam for the Hemi. Ron

 

[lewtot184]

you really can't compare some of those old racer brown profiles to modern profiles. their advertised numbers aren't taken at the same lift as a comp cams, crane or mopar performance. probably the closest modern comparison to that cam would be the mopar 284-.484/108lsa hydraulic.

 

[696pack]

Keep in mind that if you are class racing and want to run in a stock class you have to retain the stock lift. Duration and lob seperation can be anything. Don't get carried away with the SOUND of the cam because that is not always what makes a big performance difference.

 

[shag766]

Keep in mind that if you are class racing and want to run in a stock class you have to retain the stock lift. Duration and lob seperation can be anything. Don't get carried away with the SOUND of the cam because that is not always what makes a big performance difference.

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i know don't get carried away on the sound. i guess i was just expecting more. i really don't know anything about racer brown stuff. not a big deal when we were young and playing it was 3/4 or full race stuff. times have changed. not planning on racing, just cruising. thnx; rick:headbang:

 

[KingElvis]

View attachment 197758

Why do people quote this "284/284" number for Hemi camshaft duration, even though, according Plymouth "RTS" brochure it is 292/292? I've also seen a print ad for the '68 340 Cuda that says the duration is 284/292 for the 4spd car.

This points to a bigger issue of why Chysler 'advertised duration' is about 20 points lower than GM for similar performing cams.