COMPLETE DESTRUCTION!

We put our 350 small-block and LS1 on the dyno to see which made more power.

- JEFF SMITH

Over the past year, we assembled two very mild small-blocks aimed at the typical hot-rodder looking for a solid street engine built on a budget. Once both engines were assembled, HOT ROD Editor John McGann suggested we test both to see how they compared, which we thought was a great idea.

In case you missed the buildups on the two engines, the first was the 355ci small-block Chevy using a 1986-and-later one-piece rear-main seal block that we built to replicate the affordable crate engine that Chevrolet used to sell but has discontinued. We upgraded our engine with cast-iron Vortec cylinder heads and more compression in "Modest Mouse" (Nov. 22).

The LS engine was a slightly different approach. It started life as a Gen-III iron 5.3-liter that was machined out to an LST's bore size and fitted with a similar hydraulic roller camshaft. The 10.8:1 compression was higher mainly because we retained the smaller 5.3-liter cylinder heads, which have a smaller chamber size. Both engines used dual-plane intake manifolds and the same Holley 750-cfm mechanical-secondary carburetor.

Because the small-block Chevy was originally assembled with a flat-tappet hydraulic cam, we thought the addition of a hydraulic roller cam with similar timing numbers would make this comparison a bit more fair for the little small-block. This conversion was easy since the engine we chose to build was a post1986 one-piece rear-main seal block designed to employ a factory hydraulic roller camshaft.

Once that was completed, we arranged with Summit Racing to test both engines on their SuperFlow Powermark engine dyno at Trick Flow Specialties in Tallmadge, Ohio.