The 340

[DaveBishop]

I originally put the engine in Kev's car for Tony who owned it before him it was a 273 car and I put the 318 in. At the time I also put a Edelbrock performer cam, manifold and 600 holly it ran 15.3 It was like that when Kev bought it. When Kev had it he changed the 904 gearbox with one he got of Blue which I had built and had put a low ratio gear set out of a six pot jeep. Blue would know what else he done to the engine but I know that before he ran the 11 second run he borrowed loads of bits of me don't know if he used any of them. He did have to put a rod and piston in the engine. Kev I hope will add to this post and tell all.

[pete walton]

What i loved about that car was that it was a true budget built car, no fancy bolt on ali heads,no fancy cranks,,,,just good ole fashion fettling....God knows how fast he would have gone with that PRO charged small block moter he had ....

[pete walton]

Heres a picture from back in the day,,,,Martins yellow Satty along side the Taxi ...

[Guy]

Kev is partly responsible for my unhealthy addiction to this stuff.....along with Pete Wiseman and Blue....

my one and only (to date) red light

Kev and me used to have some good old battles in the early days before he took his drug habit, still have one of his cards he handed out to those he beat

[shovelheadrob]

In around 1986 I had a Dodge D100 truck with a T/A 340 engine in it ran a 13.7 quarter @ 72 mile an hour I had to slow down before crossing the line because I had to much front wheel wobble.

That truck was a lot of fun, I had it from Bish, I once raced a Sierra Cosworth with it, he pulled out to overtake me just as I nailed it on a straight bit of road, I had to lift at around 110mph though as the car trailer I was towing was dancing like Bez on the happy pills, the Cosworth was a dot in the mirror.

[DaveBishop]

shovelheadrob wrote

That truck was a lot of fun, I had it from Bish, I once raced a Sierra Cosworth with it, he pulled out to overtake me just as I nailed it on a straight bit of road, I had to lift at around 110mph though as the car trailer I was towing was dancing like Bez on the happy pills, the Cosworth was a dot in the mirror.

Still have the engine. At the time it was in the truck it had a edelbrock performer manifold and cam, small valve heads (The T/A heads were off being ported at the time) and a standard converter and 4.10 gears

[Carl]

It's all to do with stroke ratio. The 360 has a longer stroke which will make more torque than the 340,

Bananarama!.

You didn't listen to a word from the last thread. The length of the stroke has nothing to do with how or where the engine makes torque.

Torque = power. ALL that power comes from how much fuel you burn. Period.

Burning fuel does not care about the length of the rod or the stroke.

Sorry Dave its not Bananarama!. Yes we know an engines power comes from fuel it burns and how much power it makes is determined by the heads, cam, carb, etc. That's not the point im making, as I said stroke/bore ratio is also a factor here.

Short stroke or over square engines of which the 340 is one, have a larger bore diameter than its stroke length so this combination can allow bigger valves Shorter stroke means you have to generate more rpm to get the torque and horsepower. The faster you can spin an engine the more horsepower it will make, that's why they are high revving screamers. And the rpm is the product of the bore/stroke and how much power is made in that range is determined by the heads CR, carb and cam etc as already said. And its at high rpm's where they make their peak torque and why they where used in stock car racing and not the 360.

So therefore the 360 is a long stroke or under square engine, smaller bore than its stroke and smaller valves and combustion chamber. The longer the distance the piston travels on its stroke. The bigger the diameter the crankshaft has to be, and the longer the rod has to be therefore a longer stroke, more stroke equals less rpm and less horse power but more torque at a lower power band.

Now let me quote Les

"That's why a 360 is more referred to as a torque engine, cos of there lower 8.5:1 CR. and longer stroke. Less demand, slower and less bang at the top.=less hp".

Sorry quoting you Les but im being patronized for saying the same thing as you.

Does this therefore mean Les and everything i've read is wrong then, why is Les right and im not?

[Dave-R]

Nothing you have said there is correct. It is all so factually wrong I don't even know where to start.

[Carl]

You winding me up?

Les obviously wrong too?

[TYREMAN]

Im no Expert but for us Torque is more important than HP for our big heavy cars.

Look at F1 cars with 750BHP but only the Torque of a Ford 302

Here is an example (not me from the Net)

"Current F1 engines produce somewhere between 250-290 lb-ft of torque with that figure peaking at around 14,500rpm. Expect bhp to peak around 3000rpm higher than the torque peak e.g. 17,500rpm, and the rev limiter to cut in a further 500-1000rpm higher than that.
There's no need for huge torque in an F1 car, its light weight and always in the optimum gear to make use of the BHP."

So if you woned a Buick GSX Stage 1(455cu) it may only have 400+ BHP but 560 lb-ft thats double of an F1 car be cool owning one and and saying its twice as powerful as an F1 car same story for Hemi.If you stuck the 750 BHP motor from the F1 car in ther GSX then its performance would suffer even though it would have gained 350 BHP it needs to be a torque monster.S

[Dave81]

I like your combo Les but I would go 11.5:1 with modern alloy heads and a roller tappet cam to get those valves opening/closing as fast as possible so that the effective duration is longer.

Over 400hp should be easy and still streetable.

Dave/Les,

From what i have read there is an issue with high CR and detonation on normal fuel. Keep in mind most of my info is from the US sites and there RON ratings are different, at what point would you run into issues putting in standard UK 95.

My understanding (very limited) was high 9's at the most low 10's. Thus..........would the 11.5:1 dave mentions require closer to 100 RON to run daily?

Dave not sure myself about our normal unleaded, as haven't run anything for a long time. I believe super unleaded would be ok at around 10.5:1 with Ally heads and V-power up to 11 maybe 11.5:1 possibly, but of course you may have to back the timing off a touch on a particular combo which ain't the best but it would work. You can get away with running more CR with Ally heads.

Not sure what you mean about high 9's low 10's?...but I would think an A bod 340/360 with 11.5:1, ported Ally heads and a .600 roller Cam and all the rest should deffo run in the 11's quite easy on mtr and 10's with N20. and still be streetable, depends what your version of streetable is.

I personally could only manage around 55mph on the street at 4000rpm cruising but only had 26" tall street tyres, a set of 30" truck tyres would've sorted that though....wasn't too keen on that for long distances, but petrol was only around .80p/ltr then if I remember well.

Les

Sorry Les by Hi 9's low 10's i was talking purely CR, So 9:7.1 to about 10:2.1. Just interested on how far you can go on UK 95 rather than Super/V Power (tuning within constraints of RON)!

[Les Szabo]

thats ok Dave, I would suggest around the figures you mention, 9.7>10.2:1 max? as being in the ball park for 95 Unleaded with Iron Heads.

Unfortunately I have no personal experience on this as I was using 4 star on the 340 which was 98 I think.

Installing a hotter Cam with more duration should not be a problem on the tuning side.

Very hard to say how far you can go on a particular combo with 95, just keep your motor Cool, don't run your carb too lean it will have the reverse effect on fuel and up running temperatures which you obviously don't want.

Les

[Dave-R]

You winding me up?

Les obviously wrong too?

I don't remember Les saying that two identical engines (same cc and everything else) can produce different amounts of torque simply by one engine having a longer stroke.

And I doubt Les would be daft enough to fit a LONGER con rod in a stroked engine. Unless he really wanted the piston to punch through the head?

You have it all back to front. It is not the long stroke that makes the low rpm torque. It is having low rpm torque in the design that requires a longer stroke. Otherwise piston speed is too slow for efficiency at the low rpms the engine is designed for.

Likewise if you are designing a high RPM engine you need to shorten the stroke to limit piston speed.

You are putting the cart before the horse.

But I have told you this before and you didn't listen so i don't know why I am wasting my breath now.

The one thing that makes an engine produce more torque at a lower rpm is increasing its cubic capacity.
The bigger the engine - the more low rpm torque it makes and the "milder" it is.
To make up for it you use a bigger duration cam to move peak torque back up the rpm scale.

The 360 makes more torque because it is bigger than the 340 and simply because of that the torque peak will be at lower rpm.

[Jon Connolly]

Carl

What are you hoping for 1/4 mile timewise from your set up ??

I can`t remember ... is it a 340 stroker with Edelbrock heads ??

[MilesnMiles]

Carl's is Simons old 340 stroker isn' it? I thought Simon was having trouble cracking the 13s, dont think it ws getting off the line quick enough (anyone remember?), be intersting to see what it can do when it does hook up.
I can't see my own Roadrunner with a mild 340 and 3.23 rear getting more than high 14's.
I guess all will be revealed, good to see Guys old Cuda in the video's