American Speed vs LS

[740EVTORQUES]

Newbie question, how do these compare in terms of usability, reliability etc? No worries about ultimate power as they’re all fast enough but don’t want to skimp on the purchase price and end up with a lot more headaches!

Thank you.

[TR3B]

My crate LT has been stellar, I picked it up at the Chevy dealer down the street (so delivery was easy) and for the first year the engine and ancillaries were covered by the factory warranty. I had a belt tensioner break during install and they covered the replacement without any hassle. Don't know what part of the world you're in but if you live near a GM dealership these things might be a plus.

[Panamax]

I'd keep things as simple as possible, which means a standard Chevy engine. Any of them should get an Ultima moving along nicely and with good reliability.

[740EVTORQUES]

So stay clear of American Speed is the general advice?

Thank you

[UltimaCH]

In the past the Factory recommended builders to use American Speed, but don't know what their position is today though

[740EVTORQUES]

UltimaCH said:

In the past the Factory recommended builders to use American Speed, but don't know what their position is today though

The reason I ask is that I've found a nearly new GTR with an American Speed engine. I'm not chasing Ultima(the) power or performance, I'm sure they're all good enough, but just want that Ultima experience without too many headaches.

I'm more than happy to do the odd bit of carb balancing if that's what's required though.

[845ste]

I remember that here in PH, in the past, many owners had problems with HP that American Speed ​​declared on paper: on dyno they never corresponded..... and the differences were notable -10/15%

[confusionhunter]

I wouldnt stay clear per say, I think the issue as said already the power numbers werer alittle inflated, but Most Ultimas pre LS will have American speed engines, and actually they are just a builders, the SBC platform has been around far longer than the lS platform and is still one of the most tunable bang for buck engines available IMHO. You'll pay a lot more for an LS engine. I for one enjoyed my Carbed SBC until I upgraded to Efi. The engine itself has been rock solid, had a few issues with ancilleries. But I kno of a low mileage LS thats snapped a valve spring, so each engine will have its foibles, Id wory more how its been looked after.

[GTR720]

I had a GTR720 with AS 730ps engine and Holly carb. Was a great engine but the cam was very lairy. The car wasn't content to cruise at low speeds, was tuned for the track and was much happier accelerating throught the gears. The who car shook on tick over. I could only get into 6th above 60mph and then it still liked to kangaroo. I also found I had to turn the aircon off each each time just before I pulled up to stop otherwise the engine would stall. Proper full on race engine.

I now have an RS with LS3 strokered to 6.8 and fully forged with Camems ecu. It will go into 5th at 30mph. Next step is considering twin turbos.