There is documented data of a 330 HP 350 HO engine upgraded to a GM Hotcam and 1.6 rockers making 401 hp and 428 tq with the crappy flowing Mexican 062 heads that came on that engine. The comp cam I mentioned is slightly more aggressive for the same 0.050" duration as the hotcam.
Back in the day when the L31 head swaps were just getting popular Hotrod Magazine took a mid 70s 350, put a Comp XE268 cam and vortecs on it. They managed 394 hp out of that. Vortecs do not need huge cams to make 380-400 hp.
Vortec Blazer put a marine intake and XR270HR in his L31 swapped ~1987 S10 Blazer and went from 210 whp to 311 whp. He gained 100 hp at the wheels and from what I have learned swapping a ported stock manifold to a ported Marine manifold, I gained nearly nothing with the Marine manifold on my 383 making ~500 hp. There was another guy that went by VortecStroker or something like that back in the day. When his truck had the stock L31 bottom end and heads he put a GM LT4 Hotcam in the truck. It made 305 RWHP with the stock heads, intake manifold and injection. That was around 380 hp at the crank on his truck and possibly a touch more.
The EFI connection owner, Mike Noonan put together a L31 with a Hotcam and a Ramjet intake in his S10. It made 311 whp.
Edit- Mike Noonans S10 was 311 whp. I was remembering his torque number when I said 330. What Mike Noonan got from Hecho en Mexico 062s and a LT4 Hotcam. So 218/228 @ 0.050 will make over 300 whp in a L31.
I had a stock long runner TPI setup on a 10:1 355 I setup in a 1987 Firebird that made 290 whp through a TH400 with a 2,800 rpm converter. It had the older design Dart Iron Eagle 180 heads which are arguably worse flowing than Vortecs and a LT4 Hotcam. for reference a stock 113 aluminum head L98 makes about 240 whp through a 700r4 with free flowing exhaust. Flow numbers show the 113s are about the same flow as the 180 iron eagles used on that engine. So a little compression, shorty headers and a LT4 hotcam added 50whp through a slippy, loose converter and TH400.
This was Mike's result with his S10.
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