FConn3

Just to have a little conversation going, I'd just like to see how much hp you think my car will put out when its all done. Or anything else you think I could do to make more power before it goes in. I've got a 355, TRW forged pistons, steel crank, Weiand Team G intake, Holley 750 carb, COMP nitrous cam 288/315 duration .520/.540 lift, COMP 1.6 roller rockers, Flowtech shorty headers (temporary), and the heads are 292 GM angle plug heads that have been ported and polished to match the intake. Let's just say theres gonna be alot of airflow. lol. The picture is nowhere near what it looks like now just figured i'd show it. The motor ran 11s in the car it was in.

FConn3

Someone say something, lol.

84Camarodriver

380 hp?

FConn3

That's what I was thinking. I'm hoping for 400. I plan on buying under drive pulleys. anybody got any suggestions?

DeltaElite121

UD pulleys won't give you any more power. Sometimes they've been known to cause charging issues depending on how things are routed.


Oh, and there's no telling how much HP you'll make when we know very little about your cylinder heads outside of "ported". Do you have a flowsheet as list of changes done to the heads?

ASE doc

It would be interesting to see flow chart results on those heads. They are old technology and generally not as good as any of the aftermarket heads available today. You say the car that this engine was in before ran 11s. What was the weight of the car and was it running nitrous?

Orr89RocZ

iTrader: (20)

Not a huge fan of the 292 heads with that big single plane intake and cam. Cam aint to bad, its a good size for the 355 motor and intake, especially with the 1.6 rockers. However not sure how those heads are gonna do on this setup. Depends on how much work was done to them but a simple port match isnt gonna help much. They can do some ok numbers after a good port reworking and maybe a valve size change but its alot of investment into an old casting...

Cam is optimized for nitrous so all motor its probably gonna be abit sluggish. That 113 lsa and wide split can hurt mid range and top end power. With the heads being small while the intake and cam abit larger, that motor will benefit from a tight lsa cam...need more overlap. Being carb'd it would normally want a 106-110 lsa anyway.

FConn3

It was a 50' Chevy truck with no bottle. Ran 11.80

Orr89RocZ

iTrader: (20)

Heads must have some decent work done to them. Can you find out the weight of the truck? most thirdgens are much lighter than trucks so I'd bet that motor would go mid low 11's in a lighter 3rd gen but its really hard to say.

On paper, I wouldnt think it would be much better than lower/mid 12's without knowing the headwork done. Surprised it has gone 11.8's in a truck

ASE doc

That is almost unreal for a 355 with those old heads. These are the heads that I still see
on old hot rods with flat tappet cams and the owner believes he is making 450HP when in fact he's closer to 350.

DeltaElite121

He probably has everything perfect on the truck... gutted, suspension done, slicks, etc. I would say it's entirely possible, but he probably squeezed every bit of potential out of his combination getting those times.

Ronnie Brennan

at the flywheel it should be around 400 give or take 25hp. after that it all depends on what you are running. Gears, tranny etc, even wheel/tire sizes I just built a 355 for my car, and was estimating about 400-425hp but with my 700r4 and 3.23 gears in rearend and my tires being 295/50R15's in rear that 400hp is now down around 300 at the wheels. Oh and 2700 stall TCI converter as well.

FConn3

have a turbo 350 with 3.73 gears.

Orr89RocZ

iTrader: (20)

Yeah I can see 400hp or more if the work done to the port was good. Figure thats lower 300's whp. I've been 12.1 in good air on a not optimized combo and it only dyno'd 308whp last weekend. Granted it was dyno'd in a hot air shop 1200+ ft higher in elevation than where it was run at the track (PA vs TX) but the car was 3560lbs and not optimized for ET.

I can see it being possible. Touching 11's isnt all that hard to do if the car is somewhat light and things are optimized. Another car around 3400 lbs went 12.2's suffering bad valvefloat and weak 60's. 330whp is all it had dyno'd on a warmer day but at same location. If it seen the cold air i had, it was a high 11's car all day.

FConn3

Im gonna be spraying a 175 shot at the track.

paul_huryk

Not a fan of those heads, but if ported right with the came and in your car could be 400hp and maybe dip into the 11's on a good day.

Don't forget that 200cfm per intake port will allow you to possibly hit 400hp, more flow is worth more potential power...

FConn3

yeah, they're done right. I'm gonna eventually buy a set of aluminum heads and a solid roller cam.

ASE doc

The cylinder head choices available today is mind boggling. AFR for one, offers CNC ported intakes and 2.10" intake valves in a 230cc head for $2,100. That may seem like a chunk of money but considering what it would cost to put this head together from a bare casting, it's an excellent price. Matched with the right cam(solid roller would be the way to go), this head would support a solid 600hp.

FConn3

I'm thinking 400 to the wheels not an engine dyno.

ASE doc

WHP is about 80-100 less than flywheel HP due to drivetrain parasitic power loss. Manual trans cars are closer to the 80 mark, automatic trans cars are closer to the 100 mark. So to make 400whp, you need to make 500 at the crank. That's easy with today's heads and roller cam choices. Not so easy with long runner TPI though. I'm about capped out short of siamesing runners or swapping to a Stealth Ram or Mini Ram. But, I built this engine to prove that long runner TPI could break the 400HP mark and I succeeded very well at that.

cuisinartvette

Ditto and doubtful without a LOT of spray


Port matching doesnt do a whole lot
stock those heads dont do that great.

If you ported them heavily they could run decent..for thier day not now

A modern cyl hea and solid roller youd blow most things you came across in the weeds.

Easy to build an 11 or 12 sec car these days.