Engine masters article i read today. They took an old dog of a 305 with a carb and stock heads/cam and captured 221 peak hp with a set of long tubes.

Took the same engine and added vortec 305 heads, comp XE268H (224/228), edelbrock airgap manifold and a 650 cfm carb and got 372 peak hp at 6100 rpm and peak TQ of 350 at 4500 rpm using the dyno longtubes also.

The only other thing they did was mill the heads a bit.

Thats a great combo for all you 305 guys. If id read that sooner id probably have bought those goodies instead of switching to a rebuilt 5.7L that makes 130 hp less and cost me $3500 (with install) + another $200 or so in new sensors etc.

 

I have been trying to get across that the Vortec 305 heads flow well and work well on a 305 for some time.

 

I beleive that was also in Car Craft (I'm going to go check and post the link if I find it).

The Vortec heads they used for the test were 350 Vortec heads- that's why they milled them down to ~58cc to keep compression up.

They also used the Westech facility's dyno which always seems to spit out some very aggressive numbers. As usual, open exhaust, no accessories or air cleaner. Figure they got 222HP to start with from a motor that was originally rated maybe 150-160 and set your fudge factor dial from there.

Still, nice gains from baseline.

 

It was in Popular Hot Rodding.....

http://www.popularhotrodding.com/eng...engine_blocks/

 

i'd say that figure is around 50-60 hp too high, add in accessories, air cleaner, realistic exhaust, numbers not corrected to perfect situations and it's easy to see the fudge factor.

 

so its basically gross hp. just like how gm did it in the 60's

 

Was the cam even streetable ?

 

Definately so, it is only a Comp Extreme Energy 268. I had the retro-fit roller version of the XE 274 in my 305 in my VAN. The 268 is more than street-able in a F-body with a 305 and 9.5:1 compression.

It pulled 14 in/hg of vacuum at 800 rpm and made something like 290 ft/lbs as low as 2,600 rpm.

Toss a roller cam in a roller cam 305 short block and it would make even more torque, more vacuum, and perform better.

 

There are a bunch of "holes" in this whole thing. And, nothing new.

First, the originator's statement about a $3500 350 with 120 fewer horses - man, talk about getting taken! 260 horse Goodwrench crate, $1400. That means $2100 for the install? Wow, need to shop around more, or start doing your own work. And, if you think that magazine 305 is going to make 372 HP with TPI - well, need we say more?

The magazine writers don't seem to know their engines very well, either. They talk about the lame dished pistons in the 305 they built, and would have been better with later roller engine pistons - guess what, those were the same pistons used in later roller engines!

Ditto to the statements others made about the dyno numbers themselves.

And, of course, the old "why do this to a 305" thing. I've long said you can get more power out of a 305 than you can for the same money spent putting in a 350 - but that's only because you have to do all of the things to the 350 that you have to do to the 305 for any kind of performance, plus buy the 350. But, that same set-up done to a 350 would have been well over 400 HP, and would have been more streetable than the 305 - while getting essentially the same fuel economy in "normal" driving.

 

Got news, alot of the 305s had flat-tops in them.

This was my stock piston in my stock 305. Had 275,000 miles on them in this picture.



I put down 191 RWHP/268 RWTQ with the un-modified stock high mileage long block. Just headers, 305 TBI setup w/ 350 injectors, and prom tuning. Stock 601 heads. Stock 929 camshaft. Flowtech 11500 headers which are 1.5" primaries about 29" long, 3" collectors. That actually falls in line with their un-modified 305 pretty well.

 

I think i have seen 428HP and around 450FT lbs on a 350, same heads, i believe the same cam, maybe 226 230 @.050, an overseen factor in a 305ci motor is that it is closer to square (same bore/stroke) which makes closer hp and tq #s, such as a 572 big block=4.5 bore 4.5 stroke, another reason a 383 has such great gains, the stroke is closer the bore (3.75 stroke/4.000std bore). I will post my Vortec 383 rwhp #s when the engine is broken in and the transmission holds up, the heads are heavily ported for such a thin casting and the cam is comp XE flat tappet 230-236@.050, my friends 81 malibu will also be getting dyno testing with a 355, and trick flow twisted wedge heads, we are curious to see the difference and i am sure there are others here who would like to know for the possible applications of their own, i am also dieing to know.

 

Heavily dished pistons were used in all (?) 305s up until 1983+ in the carbureted L69 HO motor which got flattops and about 9.5:1 compression. Carbureted LG4s still got dished pistons up until 1985 when they got flattops too. Typical compression ratio with the deep dish pistons was ~8.5:1. Early 305 TPI engines also got flattops. From about 87-up, when they went to roller cam blocks and FI across the board they all (?) got dished pistons but with less of a dish than the early motors and GM rated them at 9.3:1.

 

As far as my setup, I paid around $1500 for a rebuilt tpi motor with a warranty. I'm trying to forget about how much i paid the shop considering it was a crappy install (they didnt even tighten down the engine block bolts, set the timing correctly, broke the ignition rotor, and failed to shim the starter correctly). With installation fees, + gaskets, sensors, chip, manifold, the entire thing must have been around 3 grand (maybe it just felt like 3500 . Like I said I am trying to forget about it. The funny thing was is was a reputable shop. Been in business of doing engine/tranny installs for like 30+ years. I did my homework best as I could. But it was my first engine swap....things dont go as well as you'd like despite all the time you put into a project. Frustrating.

I guess I am just amazed at what these engines are capable of with head/exhaust/cam combos.

I wonder what percent decrease in HP you'd see on that 305 with accessories, drivetrain loss.

 

About a 25% loss. RWHP around 275.

There was an earlier mag article where they got over 400 GFWHP from a 305, then grenaded the poor thing while still on the dyno. That's the part that seldom gets told.

Fast355 and others have gone to greater lengths to make sure theirs don't do that.

But, again, it's the old same-dollars-in-a-350 argument. Once you have to start beefing up the 305 shortblock to take the power you're making, it's time to start spending that money on a 350.