Um, well, hello to you! The alloy head for the log head block 200/250, or the 300 Ford? Both are going to be awesome if they pass the durability tests on the headgaskets and alloy castings. Even if there were some hick-ups, there are many millions of engine blocks still around to form a great engine.
Bascially, I'll describe how to calculate HP, and then tell you what is likely to happen for non turbo 200, 250 or 300 cube non crossflow engines with the Classic Inlines head.
hp is RPM times Cubic inches,
divided by its Aspirational Index. (AI Number, lower the more efficent the engine is)
This is anywhere from 11000 on a side valve flat head Ford V8 to 3600 on an AVESCO V8.
A well worked 12 port head on an XT5 Holden commodore block can give 295 hp at 7000 rpm with triple Weber DCOE 45's and a 312 degree 'HX' spec XU1 Bathurst Spec Cam. (202 cubes times 7000 rpm, divided by 295 hp is AI number 4800)
The most basic 265 Hemi can do 290 hp net at the flywheel at 5300 rpm with just some DCOE 45's, a set of headers, and the great E49 great cam (306 degrees) and no other major head mods. (265 times 5300 rpm, divided by 290 hp is AI number 4800)
A 2004 Horsepower Heros dyno run of a 265 Hemi in a red VG Pacer gave something like 320 rear wheel hp without Nitrous or a turbo. Thats over 400 flywheel hp. I think they took it out to 277 cubes, and ran the numbers with the engine in a very tired state. (277 cubes times 5500 rpm, divided by 400 hp is an AI number of 3800)
The Commodore Challenge 253 engine started in 1995 as a 280 flywheel hp engine, and is now well over 300 hp at about 6500 rpm, with just a Mr Punyverse 465 cfm 4-jug Holley. (253 cubes times 6500, divided by 300 hp is an AI number of only 5482)
The Group C Torana A9X 308 was well 430 flywheel hp with twin IDA 48 Webers. At about 6700 rpm or so. (308 times 6700 rpm divided by 430 is an AI Number of 4800)
Holdens last 1987 (4-bbl 725 cfm Rochester) Group A VL gave 462 flywheel hp at 6900 rpm, so developement yields results (308 times 6900 rpm, divided by 462 hp, is an AI Number of 4600)
Ford or Holden AVESCO engines rev to 7500 rpm from 302 cubes, and have about 630 hp, so the AI Number is 3600 or so. Even the old Cosworth DFV 3000 cc engine couldn't do that, reving to 11000 rpm, and yielding less than 550 hp.
The 300 is well over 13% bigger than a 265 Hemi, and has the same rod ratio, same bore spacings, and is pretty strong asside from some marginal pistons. If you improve airflow and balance the carb and cam, power goes proportinally. Any time you use independent runner carbs which are sized right, you can get another 25% on what the best EFI or 4-bbl carb can make.
I know that the 300 is able to rev to 5500 or maybee 6500 rpm when the cam and timing gear and pistons are upgraded. There are forged cranks around and it has a significant race history. Looking at those engines above, its pretty easy to get an AI number of 4800 even if reving to only 5500rpm, so I know that 344 hp is within reach if there are three big 2-bbl carbs, or perhaps the best 4-bbl manifold around. You'd need a set of carbs which have 43 mm chokes, and that means you'll have to use DHLA 48's or rare DCOE 48 or DCO 50's, or three IDA 51 carbs. Probably, just one 4-bbl carb with about 600 to 750 cfm will do that.
With more work, 6500 rpm may give 423 to 514 hp, depending on how massive the cam and who the independent runner carb set-ups are. Of course, the wide ratio 4 stage AOD-E gearboxes which are found behind many 5.0's allow you to run such peaky engines on the road, and take anythig a six can throw at it. So the 300, no heaver than a 265 Chrysler Hemi, is able to take the strongest gearbox know to man, and should be the ultimate Econo engine made, anyhwere, ever. With the alloy head, ofcourse.
Go to the Big Six forum, taken an evening out and do a full search of The Frenchtown Flyers 1000 posts. It'll take a while, but somwhere there is nested the Mad Frenchmans tiny 103" wheel base Maverick two door. Halfway between a Totana LJ and an Valiant Charger. It has a 300 three ID series Webers reaching for the sky, an it Eats Eights for Entre'.
On the Argentine Todo Falcon site, even single 3 liter engines based on the humble old XT Falcon 188 are psuhing 300 hp at 7000 rpm with just one IDF Weber.
Get ready for it, there are over 15 million of those 240/300 engines around, and they aren't cannon fodder, they are the cannon!
As for the little 200 and 250, they will be able to eclipse the X=flow engine by virture of the ports and flow charateristics. So there is a Toroana XUI with Webers style power there. 300 hp from a 200, and 350hp form a 250. You can wack in OHC cranks, and rev the crap out of it more easily than the bigger 300.
Hi Addo.Did that 300 have a solid platinum head?
From memory it had 112K miles on it, too.
