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I've been learning about camshaft selection for a 454 in a RV.
Crane Cams 10304, $121.08, made in USA
COMP Cams 11-203-3, $142.99
Summit Racing SUM-133, $74.99, made in USA
Melling 22127, $101.42
All are Hydraulic flat tappet camshafts for the 454. This design has been out of vehicular production at GM for 15 years. Generally we don't want the same kind of camshaft we'd be putting in a Camaro. Less overlap enhances the low end of the RPM range and drivability. The smaller the lobe separation angle, the better, and I don't know why.
I am leaning to the Crane or the Melling shaft for my Barth. Older designs seem to be symmetrical, with the exhaust cam lobe matching the intake. More recent thinking in camshaft design puts a larger and longer lobe there.
I noted that my 33 year old valve springs have 33K miles on them. The Crane tech staff says that there is no need to replace the valve springs, the Melling staff says I should.
I think I'll also replace the water pump, and the timing chain at the same time. The valve lifters have to be replaced at the same time as the camshaft. I already ordered the Weiand intake manifold 8122WND to work with the peanut port heads. All the advice says that for my 1988 Barth with the 1987 Chevrolet engine, I'd have those heads. I confirmed this with looking up the intake manifold casting number 14087487, and pictures of this show the small intake manifold ports on the internet.
On the topic of "being out of production for 15 years".... Who knows how long the aftermarket is going to support this. It might be a good idea to "collect" another set of "spares" when it comes to some of these parts. I already have one set. Prices seem good on Ebay for some items, that are "new old stock" and being sold by liquidators.
Duration 266 int./266 exh.
Basic Operating RPM Range 1,200-4,800
Duration at 050 inch Lift 210 int./210 exh.
Lobe Separation (degrees) 110
Valve Lift with Factory Rocker Arm Ratio 0.499 int./0.499 exh.
COMP Cams 11-203-3
Duration: 260 int./260 exh.
Basic Operating RPM Range: 1,200-5,200
Duration at 050 inch Lift: 212 int./212 exh.
Lobe Separation (degrees): 110
Valve Lift with Factory Rocker Arm Ratio: 0.475 int./0.475 exh.
Summit Racing SUM-1300
Duration: 276 int./280 exh.
Basic Operating RPM Range: 1,000-4,500
Duration at 050 inch Lift: 208 int./218 exh.
Lobe Separation (degrees): 112
Valve Lift with Factory Rocker Arm Ratio: 0.475 int./0.500 exh.
Duration: 261 int./272 exh.
Basic Operating RPM Range: 700-4,500
Duration at 050 inch Lift: 190 int./202 exh.
Lobe Separation (degrees): 110
Valve Lift with Factory Rocker Arm Ratio: 0.439 int./0.465 exh.
1987 Barth 27' P32 Chassis
Former State Police Command Post
When I replaced my engine in the 86 Regal I installed a 454HO crate motor. Good strong motor at high end (438 hp!) pulled like train to 90+ but struggled to pull a hill at 55. Power band kicked in about 60. It had a camshaft with lots of lift, duration and overlap. Too much for a heavy sled.
Valve Lift (in.): .510 intake / .540 exhaust
Duration (@.050 in.): 211° intake / 230° exhaust
When I pulled the heads I replaced the cam with another from the HT502 engine, designed for more torque. Still good for 406 hp but lower power band.
Valve Lift (in.): .480 intake / .483 exhaust
Duration (@.050 in.): 204° intake / 209° exhaust
With this cam the engine ran really well. Pulled strong from 55 mph all the way to 80+. Before if I started a hill below 60 I would often bog down. With that cam you could start at 50-55 and be at 70 by the top of the hill!
These are roller cams but I think these specs would work well.
As to being obsolete, the Chevy Big Block dates from about late 60's. From Gen I to Gen VI there are tons of them out there, and GM is still selling crate engines. I think there will be a continuing aftermarket demand and supply for many more years.
"98" Monarch 37
Spartan MM, 6 spd Allison
Cummins 8.3 300 hp
Formally known as "Humbojb"
Good stuff to know. Hopefully, I will be long gone before "Nameless" needs an engine rebuild.
Jim (aka Hum)
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