340 4 barrel and 340 6 barrel: were they really UNDERrated?
Here's a dyno of a stock 273 Commando with manifolds and headers.
It basically hit it's stock hp number 233.4 hp.
A 340 only makes 40 hp more ?
https://www.hotrod.com/articles/testing-mopar-273-power-pak-dyno/
"TTi headers are about the best on the market for our unconventional Mopars, but we were warned to make sure our small 273 exhaust port windows fit properly. Sure enough, the generous TTi flanges (which are sized for 340/360 heads) left large leak paths. We remedied them by welding up the bottoms (pen shows them in photo) to match the 273 port windows. The extra exhaust flow delivered 244.2 hp at 5,100 rpm and 283.4 lb-ft at 4,000 rpm, gains of 10.8 hp and 6.6 lb-ft."
Here's a dyno of a stock 273 Commando with manifolds and headers.
It basically hit it's stock hp number 233.4 hp.
A 340 only makes 40 hp more ?
https://www.hotrod.com/articles/testing-mopar-273-power-pak-dyno/
"TTi headers are about the best on the market for our unconventional Mopars, but we were warned to make sure our small 273 exhaust port windows fit properly. Sure enough, the generous TTi flanges (which are sized for 340/360 heads) left large leak paths. We remedied them by welding up the bottoms (pen shows them in photo) to match the 273 port windows. The extra exhaust flow delivered 244.2 hp at 5,100 rpm and 283.4 lb-ft at 4,000 rpm, gains of 10.8 hp and 6.6 lb-ft."