Can you get the same kind of gains from Small Block Chevy cam swaps as the LS guys? Find out in this episode of Speed Secrets with Richard Holdener.
Chevys revolutionary LS based engines seem to be an anomaly. With the way these engines respond to even mild cams, it makes you wonder how it can be so superior to its predecessor in this way. Richard Holdener at Speed Secrets and Comp Cams take a closer look at the two small blocks to see if they can get the original small block chevy to respond to a cam swap just as well as an LS.
One of the reasons LS engines respond the way they do to cam timing is because of the good factory head flow but LS heads were not the only notable heads that GM made. So Richard headed to the local junkyard in search for a small block and Purposely chose a late model Vortec headed version as a starting point because of the better flowing heads. After converting the originally EFI equipped small block to hold a 4 barrel carburetor, matching intake and distributer, it was on to the dyno to get a baseline. With the stock camshaft, designed for low speed torque production, the small block made 278 HP @ 4,600 RPM and 353 Lb-Ft @ 3,700 RPM.
To hopefully wake this engine up, a Comp Xtreme Grind cam seems like a good start. Comp Cams XE268H offers the SBC a .477/.480 lift and 224/231 duration with a 110 LSA. Along with new Comp lifters and valve springs installed, Richard pours in a bottle of Comps break in oil for a little added insurance and moves the SBC to the dyno, where the engine showed off just how well the LS’ predecessor can respond to a cam swap. With gains of 65 HP and 28 Lb-Ft, the original put down 343 HP and 381 Lb-Ft proving that the LS isn’t the only small block chevy that responds well to the right cam.