How much gain in horse power is to be had by taking an oem pre EFI 300, porting the head, adding EFI exhaust/headers, intake and 4v carb.

A mild cam would bump the total by how much?

Over size valves?

Using a 240 head over an oem 300?

High energy ignition?

 

Just out of curiosity, have you ever had the combo in your sig line dynoed? Looks like you've built a pretty nice engine...

 

good question F-250 restorer I sort of asked the same thing in my 'few more pony's' thread but didn't get any feed back... Once mine is done I'm going to put it on the dyno and see but from what I have been told so far is

good P&P = 50 HP

D.U.I. dizzy = 15-20 HP

index kit = 1-3 HP

I'm gonna run a holly 390 and the EFI exhaust with 2.5" all the way out the back with stock cam.... might go with some high flow valve's but not sure yet on that....

I dont know if there is a chart or somit to go by when we double the intake/exhaust flow size but I would like to see the numbers on just that myself....

I would guess for what you have posted, and from what I have been told here as well as at the shop doing my head you could get 100 more HP

just a guess tho, beside's the numbers I posted on the P&P ect.

I hope to get my head back this week and I will pick the guys brain some on the intake/exhaust HP gains from stock...(he is the best race car engine builder here)

on a side note.... last I was out there he showed me he's F250 baja racer with a built chebby 350 with a holly 390 that put's out 550 HP

He really like's the holly 390 and was happy to see me going to that on my 300.

look forward to more input from others

 

Thanks for the info.

I have read on the other forum, Fordsix.com, by knowlegeable guys, that 2.25 single exhaust is fine, or 2.00" dual.

No, never had it dyno'd. I based the build on one I read about on the net. Without the over size valves he pulled 250 hp at the flywheel.

 

You aren't going to get 100 horsepower out of that.

I'm guessing 35 horse.

 

I have dual 2.5 on my 82, down to 2" for the dual tail pipes. muffler is a flowmaster super44 with 2 in, 2 out, 2.5". this truck is LOUD. I wish I would have used a different muffler

 

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I'm glad you told me your guess. Guesses are so educational. The build I copied had been dyno'd. Look at the 'FrankenSix' build with 311 hp, and imagine what changes you would need to make so that engine only produced 250 hp? Lower compression? less cam, Dp intake and slightly smaller carb? Wow, it kind of sounds a lot like my build. How 'bout that?

This is all theoretical without a dyno, and we're just blowing smoke.

 

just what I have been told on the numbers I posted for HP gain???

35 sounds week IMO but this is all new to me so just rookie input from what I have been told and read here and the fordsix forum

The guy that is doing my head has a dyno and has already said no prob to toss on it when I'm done

I was shocked when he said 50 HP from the P&P but he did have 3 outlaw carts in the yard with 300's in them they are the fastest on the track here and one of the drivers of those is a mechanic as well as build's his own moters....

hope they are right on the HP gain as I have spent alot of money so far on my 300 in hope's of close to 100 more pony's?

Time will tell I guess 'eh

F-250 restorer I'm gonna run a single 2.5 out off of the walker Y pipe into a flow master 40 2.5 in/out.... didn't make that clear sorry.

 

Don't get smart with me. I'm respectful to you but I can change that.

I wasn't even talking to you. I was talking to hgb4x4.

 

I think 50 hp is kind of on the high side for a head job but probably do-able. I think 100 hp is right on the money for the total build. I would say between 70-130 hp depending on certain parts you use.

 

In my mind using what I know a 100hp gain out of the 300 is very attainable.
So it was a 130 horse engine now its a 230 horse.

A 300 hp 300 is attainable. Though it would be cost prohibitive. A simple 4bbl, headers or EFI pipes, and a 260 cam should put you up to a clean usuable 180 hp with about 300ftlbs on tap. Porting and polishing and dumping a hotter ignition would give you another30-60hp and proboly about an addition 20-50ftlbs. So a realisticly predictiable power for a build like hgb4x4 is in the 200-240hp with a torque in the 290-340 range.

Lumpier cams, compression increases, big valves and rocker arms could realisticly give it 300 hp and close to 400ftlbs. Add some boot at a reasonable level and one could push both numbers up by 50 I would think.

One problom is where is the powerband sitting. If your powerband is starting to sit over 3000rpm you have just ruined the driveability of the engine. Why do you think that the 460 had better power than the 351W? It only rated about 40hp more than the windsor. The thing was the windsor produced its power at a higher rpm than the 460 making it perform less admraibly. (I like the windsor.)

Other than using the oversized exhausts all you guys have logical numbers if they are used in their propper contexts.
I am not a guy that rods the gills out of their vehicle. A true 20-30 horse gain with a 5% increase in economy is much better than a 100 horse gain with no change in economy.
I am still battling away on my 2bbl intake that I am making. It is going to mount a 265cfm holley 2bbl and use EFI manifolds. Expected performance gain with the comp 252 cam I got.......15-40 horses. But I expect my milage to improve slightly over the YFA and get rid of teh terrible lean stumble that the YFA gives me during the cold months that plauge ND.

 

After being interred in a **** prison camp, a wise man named Henkl, wrote 'Man's Search for Meaning.' That experience taught him that when everything was taken from a man, the only thing that could not be taken was how he chose to perceive things.


I write what I believe. How you choose to interpret it is your problem.

 

Since when did you turn into a jerk, kevin?

Jeez man I thought we were friends.

I'm out.

 

F-250 Restorer, aren't you in southern california? There has to be a chassis dyno somewhere near to you. I would think you could get an hour or so for $100.00. I read your article in True Blue Trucks #3. I'm glad to see you're going to do a sequel. I liked how you ripped your mechanic buddy for drinking so much beer without actually naming names. Maybe you could recycle all those cans and buy a 350 (I jest). Good article. I thought the blue and white F-350 dentside featured elsewhere in that mag was your truck at first. I would have been REALLY impressed with your truck building aptitude if it were. Not that I'm not now. You get that GV unit you bought installed yet?