i was thinking of moding my 300. as you know the 300 has a 4 inch bore with a 3.98 inch stroke. i cant decide on which of the two things that i want to do. the first is stroke it to a 4.25 in stroke and a bore it .060 up to a 4.06 in bore, that would make it a 325. The other is stroke it to 4.125 and bore it .050 up to a 4.05 bore, that would make it a 315. i know its alot of work and i will need a new cam and i was going to get a aftermarket head to put on it two. which do you think would be better and how much do you think i can get out of it Horsepower and Torque wise?

 

A 300 is a stroked 240...not much left for any significant gain. The cost for such is over the top for hp gain if any. Boring .060 can be done but there is little to gain there too. These engines just do not lend themselves well to big boring and stroking like an sbc. What aftermarket head are you speaking of? Classic Inlines is developing one for the 240/300 like they did for the sb6 but it will be some time before it is available.

 

I second that. Boring and stroking with the 300 usually don't offer a lot unless you are an artist with engine tuning and parts (which some definitely are).

The best bang for the buck on the 300 is to get it to breath with opening up the head, higher flow exhaust and higher flow intake. Those are where your gains are going to come from. (Then, of course, get the cam and carb to match all that.)

 

put your cash into reworking the head as mentioned, then put some time into getting the right pistons to get your compression ratio up.

 

clifford makes a head for it and cam kit to match.

 

clifford ports/polishes the stock cylinder head.

any performance shop can modify your head and give you what clifford has to offer and likely at 1/2 the cost.

any camshaft company has a camshaft for your engine and again likely 1/2 the cost.

headers can be found at most header companies as well, again, for much less out of pocket.

clifford would have been a nice operation to be able to say, ya know, they into the six banger and know their ****. well at one time they did but that time has passed, even worse, the parts they sell are the same parts you can buy elsewhere, they just double the price and offer it to you like it gold.

I know the idea of a stroked 300 scares folks but I think it would definitely help if you pay attention to the rods/pistons selected and get the head to breathe, although, a stroker crank is not cheap, again, any performance shop can offer you this item, as it would be nothing more than a stock forged crank that has been reworked (good luck finding one, as most are cast). you could buy a friggin complete low mile bent 8 (325+CI) (250+hp) engine for the out of pocket youd put towards the crank alone. I like unique as much as the next guy but there comes a point in time when Id draw the line with the wallet.

 

Just to pile on here regarding bore/stroke. This engine makes about 1/2 hp per cubic inch. So theoretically, you will gain 12 1/2 hp for your 25 inch increase. Even if you could magic this engine up to 1 hp per CID, you gain 25 hp, and now have cylinder walls that are questionable, and higher piston speeds to go along with the higher rpms needed to generate more power.

Head work, intake, headers, cam. Proven & reliable.

 

Not wanting to argue the point of increased stroke, the benefits of the added stroke wouldnt be peak hp gain, as much as hp/torque gain across the entire rpm range.

 

If you gain torque, you gain HP.

Longer stroke is accomplished at great cost here, and will pay back at somewhere between 1/2 to maybe 1 hp per cube, what that means in torque I'm too lazy to calculate, but the point is, it's not worth the cost.

And long strokes have less to do with torque than overall displacement and tune.

GMC V6 vs. Ford 300. Big bore, short stroke vs. square = same power, same rpms.

 

Ill agree but I really dont know how that applies to this discussion? like comparing apples to oranges that happen by pure chance to taste the same, despite there having no other simillarities.

lets say for arguement sake, all variables are the same and use a small block with simillar CI to the 300.

302 vs 331 (stroker) = more hp/torque. Its that simple. It would be like your trying to convince me that a 302 makes equal power as a 351w, both sharing otherwise simillar fuel/air induction/exhaust, which essentially one is the stroked version of the other. not gonna happen.


the drawback to stroking the 300 falls into two catagories, one being cost, and two being rod ratio. Rod ratio really isnt a reason not to do something. Many stroker kits had poor rod ratios, many OE engines that were considered workhorses had poor rod ratios, that one variable doesnt mean reliability or efficiency is negatively affected.

based on what? there is no standard. that would only apply if stroke were the only variable changed, at best, build the rest of the engine to support the additional CI....you get more positive results. you have to increase your hp per cube to build a performance engine, thats a given, now which will make more power a 300 or 330 cube engine?

get out your calculator and see how minimal HP gains at lower rpm = substantial tq gains vs moderate hp gains at higher rpm. to someone in a larger vehicle or towing scenario, that would make all the difference. peak power means jack crap, avg power gain is what counts.

"worth it" is subjective, so I cant argue that but to say there is no benefit to stroking the 300 isnt exactly accurate either. the 240 and 300 happening to share a simillar block and one happening to be a stroked verion of the other, thats not a reason not to stroke the 300, by saying that, one is implying the bore and stroke have reached a maximum, which isnt true.

 

Quote:

Originally Posted by Motorhead351

Ill agree but I really dont know how that applies to this discussion? like comparing apples to oranges that happen by pure chance to taste the same, despite there having no other simillarities.

answer:
Agree, the value vs. the cost in this case would be up to the OP, and it's certainly worth looking into if he wants.

One thing about this engine, if it's the '94--it is EFI. There are cams that will work better with EFI, but they move the power up the rpm scale. So what if he kept EFI, ported the head, put in the cam, AND added stroke? Best of all worlds?

 

ROI is absolutely subjective. But, the OP didn't state what his end performance goal is other than having a bored and stroked 300 with an aftermarket head that, to the best of my knowledge, does not exist. There should be a bit more of a plan and goal over and above "having" an engine with those things just mentioned. Custom rods, custom crank, custom pistons, custom EFI, etc., can be done and end up with some very expensive bragging rights but not necessarily end up with 1.0 hp per ci when it is all said and done. Again, these engines are not SBC's or SBF's which lend themselves well to such mods with readily available parts and interchangeability of parts at reasonable prices.

 

"I see benefit from a longer stroke", the context was assumed by me, to imply the 300 engine and increasing displacement of....as that was the topic.

So you can see how the 300 vs 302 and big v6 vs 300 comments threw me. I can agree that that is a fair comment, to a point until we start talking about how small bore engines and larger valves dont mesh but it would just be a discussion about something other than what is being discussed here.

 

i am not looking to do this cheap. it is a PROJECT. i want to experiment with it. no matter what the cost its worth it to me. i have worked around racing engines (modified class), most had chevy 350, but there were 3 or 4 that had 300 powerplants that made a s*** ton of power and could run with the 350. in the modified class the 350s were not stock, the had head work, roller cams, bottom end build ups, bored 40 over and stroked, so they are no means stock. power does not mean horsepower but overall power of the engine. I want more power but i want my 300 not a damn 302 or any other engine swap. it is all worth it to me. i want something no one else has.

 

I know that in the Chevy 292 straight six with:

Bore : 3.875
Stroke : 4.120

that when the crank throw is 90 degrees to the bore centerline it creates a rather extreme angle that pushes the piston into the bore sidewall rather hard. Been known to cause issues like broken piston skirts and excessive wear, yada yada. Haven't heard anything like that about the Ford 300 though.

Stroke/Bore ratios

Chevy 292 : 1.06
Ford 300 : .995
Ford 300 w/std bore and 4.25 stroke : 1.06

I see no reason why another eighth inch on the stroke would be a problem. But I think 4.25 might be excessive unless you could bore the engine out enough to keep the stroke/bore ratio down.