[napster]

I am going to be moving to Florida and that means I’m going through the house to see what to keep and throw out.

Started to go through my auto magazines and came across an article in the April,2005 HPP. It featured a 505 CID from Spotts Performance. It was a build using the new (at the time) prototype IA II block. All I can say is WOW!!

I wish I had this article in hand when I had the 496 built for my ’73 T/A. It would have been a 505 with the IA II block. Since the build was for a Street/Strip car, there would be differences in what I would have done since I don’t race. Only items I would change to is a dual plane intake, Holly Sniper, forged steel crank, less aggressive hydraulic roller cam and SD #16 heads.

The engine I have in the car right now will stay, but if I had this information at the time of the build it would have been done. The engine is a 496 CID with a 1974 production 455 block and has a crank with a 4.5-inch stroke. I like the 4.25-inch sized crank in the article’s engine.

It was a wonderful build by Spotts Performance. Wish I did it.

[i82much]

I did my 505 a few years after that article came out, IA2, edelbrock 87 cc heads, BRC pistons from Pontiac Dude. It now has a forged eagle crank and H-beams with arp 2000 bolts, old faithful and 1.5 rockers, performer RPM with a quick fuel 850. Very basic, streetable build. I am happy.

[Steve C.]

Spotts Performance Boulevard Bully....

Edelbrock 87cc heads about 306 cfm, mild clean up only.
Comp XE 254/254 at .050 solid roller / .3880" lobe lift / 110 LS / 1.65 rockers
10.2 compression
Victor intake / AED Holley HP1000 carb
2-inch headers

It ended up at about 582 hp at 5900 rpm after dialing it in.
599 ft.lbs. torque at 4500 rpm
520 ft.lbs. tq at 3000 rpm


https://www.motortrend.com/how-to/05...street-engine/

The cam is not 'big' in a 4.250 stroke 505

I used the same cam here in a 4.210 stroke 462:

https://www.pontiacstreetperformance...455sc2003.html



.

[Steve C.]

Initial outings with the Spotts 505 were in a '71 Pro Street Firebird.
It posted a 10.79 at 123 mph with 3.70 gears on a 1.52 60-ft with a 1800-rpm launch, a 6000-rpm shift point, and while turning*5300 rpm at the traps.
This on 93-octane.

Later updated with 4.10 gears, Continental 10-inch converter with a 3200 stall and 31" rear tires. At a 3520 lb race weight.
After working out some kinks it ran 10.54 at 126 mph.


.

[Gach]

Originally Posted by Steve C.

Spotts Performance Boulevard Bully....

Edelbrock 87cc heads about 306 cfm, mild clean up only.
Comp XE 254/254 at .050 solid roller / .3880" lobe lift / 110 LS / 1.65 rockers
10.2 compression
Victor intake / AED Holley HP1000 carb
2-inch headers

It ended up at about 582 hp at 5900 rpm after dialing it in.
599 ft.lbs. torque at 4500 rpm
520 ft.lbs. tq at 3000 rpm


https://www.motortrend.com/how-to/05...street-engine/

The cam is not 'big' in a 4.250 stroke 505

I used the same cam here in a 4.210 stroke 462:

https://www.pontiacstreetperformance...455sc2003.html



.

Is that a single Patton cam ?…LOL

[Steve C.]

According to Paul, "This was not a 'build a gazillion horsepower' project. Rather it was an exercise to learn about the features and idiosyncrasies of the IA II block and building a street 505-cube engine that has vacuum for power brakes and uses a true street type cam. It didn't make huge horsepower numbers but did deliver on torque. It idles like a mild engine but can still put a well-prepped street car into the 10s."

Of interest in the above where it mentions a 'true street type cam" .
Keep in mind cubic inches eat up duration, again that 254 degree cam is not big for a 505.

The current 255 @.050 solid roller cam in my 505, depending on the dyno pull, made peak power at 5600 to 5800 rpm, average 5750 rpm. This with a Victor / 4150 carb set up in use.

Also related, as we are aware when you run a solid lifter cam you typically add additional duration over a hydraulic cam. If you want the valve lift curve to be the same, the solid( Mechanical) lifter cam will be bigger at .050".
Some might suggest 8-10 additional degrees of intake duration.


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[Gach]

Of interest…..yes its a single pattern cam…LOL I just google it.

[napster]

Steve C.

The cam I would have put into the 505 is a Butler custom grind with @.050 of 248/254 with LSA of 110. What I have in the 496 is a "tad small" with 242/248 @.050 and LSA of 112.

The reason for the change in the LSA is the article mentions the IA II block was improved for more vacuum for brakes.

Jim

[Gach]

Originally Posted by napster

Steve C.

The cam I would have put into the 505 is a Butler custom grind with @.050 of 248/254 with LSA of 110. What I have in the 496 is a "tad small" with 242/248 @.050 and LSA of 112.

The reason for the change in the LSA is the article mentions the IA II block was improved for more vacuum for brakes.

Jim

The Butler cam definitely better cam. Would’ve been smart move

[Steve C.]

napster,

I spoke with Paul not long after he built that 505. We discussed a few items but never his cam specs. On my 505 I've used both a 110 and a 112 LSA. On my last build I went with a 108 LSA in conjunction with the poor 9.7 compression ratio on the alum cylinder heads in use. The reason, according to Comp Cams if you tighten the lobe separation angle (smaller LSA number) it builds higher cylinder pressure, increases cranking compression and increases effective compression.


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