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 Yet another 455 Cam Request
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dkeys23
Tribal Scout

USA
1 Posts

Posted - 26 Jul 2016 :  5:27:53 PM  Show Profile  Reply with Quote
I have read all the posts I could find, but I still need to ask. Sorry if this is old hat to some of you, but I am planning a near future build and want to consider other's experience.

1968 Firebird in full street trim. Weekend street car. 455 +.030, 7K3 ported heads, forged rods/pistons, stock crank, 2-bolt mains w/studs, Edelbrock Performer RPM intake. Headers w/ 2.5 Flowmaster exhaust w/ balance pipe.

Compression ratio range will be a min of 9.4:1 to approx 10.0:1. This will be dialed depending on the cam to optimize DCR for pump gas (8.25:1 or so).

27.65" Rear tire w/ 3.55 gear. Manual trans with .073 OD.

I am looking for a cam that will allow decent manners around town. I'm looking for a nice healthy thump, but don't want to have to 2 ft it around town or dial the idle to 1200 (exaggerating for effect). I also need enough vacuum for power brakes.

If I've left something out, let me know. Thanks.


Steve C.
Crazy Horse

1675 Posts

Posted - 26 Jul 2016 :  6:37:37 PM  Show Profile  Reply with Quote
Adjust the static compression ratio (example, dish the pistons/mill the heads) to get a 'safe' compression ratio and use a cam more in line with your prefered build criteria.
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Tub
Sitting Bull

172 Posts

Posted - 26 Jul 2016 :  6:39:23 PM  Show Profile  Reply with Quote
For a HFT:

Howard's 410051-14 or Crane 283521, with Hylift Johnson 951R lifters.

https://www.summitracing.com/parts/hrs-410051-14/overview/make/pontiac

http://www.cranecams.com/product/cart.php?m=product_detail&p=24164

http://www.ebay.com/itm/Crane-Cams-High-Performance-Cam-Pontiac-265-455-V8-55-81-486-494-/271117502161

http://www.jegs.com/i/Crane-Cams/271/283521/10002/-1

Or an 041 grind with Rhoads lifters. These may not have the "healthy thump" you want, but will give plenty of vac, and low end torque.

http://www.ebay.com/itm/Engine-Camshaft-Stock-MELLING-SPC-8-fits-68-70-Pontiac-Firebird-6-6L-V8-/131527250214?hash=item1e9fa29126:g:e5wAAOSw7XZXgN6J&vxp=mtr

https://www.summitracing.com/parts/rhl-9518/overview/make/pontiac

https://www.summitracing.com/parts/rhl-9518l/overview/make/pontiac

https://www.summitracing.com/parts/rhl-9518xl/overview/make/pontiac

Or, how bout a real Thumpr ?

https://www.summitracing.com/parts/cca-51-601-5?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-comp-cams&gclid=Cj0KEQjwlNy8BRC676-W0JezxbwBEiQA4Ydg0UrxpEHSREtth44KPjQoOPgpPb6IxdovapJXwFX78oIaAl6n8P8HAQ

Here's a couple that'll have plenty of "thump", but even with Rhoads V-max lifters, I don't know about the vac.? Probably better for a mild bracket engine & manual brakes.

http://www.crower.com/camshafts/pontiac-287-455-hi-draulic-hauler-cam-296-hdp.html

http://www.lunatipower.com/Product.aspx?id=1765&gid=279

Of course, if you got an extra thousand or so to spend, most recommend a roller cam.

I'm with Steve C on the "safe" CR. No sense in taking a chance on engine damage, just for a few hp. IMO

I'd try to keep it down around 9.25, and I'd sacrifice the "thump" in favor of good vac, idle, and low end torque. But, that's just me.










Edited by - Tub on 22 Aug 2016 6:01:28 PM
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