1974 Plymouth Roadrunner

hjworton · Post by **hjworton** » Thu Mar 14, 13 7:35 pm

Thanks for that link MilesnMiles , loads of ideas there...

Been under he car on my back this afternoon(lifted car does have some advantages, can get pretty much under 3/4 of the length) - my idea of fun - corrosion is fairly light IMO, been at the loose stuff with a wire brush, looking a little better already. In terms of protecting the underside long term, what sort of thing would you recommend ? Waxyoyl ?

Dave81 - first few things I'm doing will be fairly soon, hopefully won't be out of action for long. Things like lighting and steering need sorting out ASAP, can't wait.

Carl · Post by **Carl** » Thu Mar 14, 13 8:29 pm

The great 340 360 debate

short strike bigger bore more HP. Smaller bore, longer stroke more torque.

Dave wrote:The 360 is not a bad engine at all. They take a decent overbore and you can get stroker kits to produce 426 cubic inches.

That is not a bad displacement for a little lightweight (for iron) engine.

Low rpm torque is what you want for a street driven car anyway.

http://www.hughesengines.com/Index/prod ... rtid=23812

That is a loooong stroke over the stock 3.580 stroke, that must be tight? 408 ci stroker is the norm on a 360 i believe?

Dave81 · Post by **Dave81** » Thu Mar 14, 13 8:40 pm

hjworton wrote:Thanks for that link MilesnMiles , loads of ideas there...

Been under he car on my back this afternoon(lifted car does have some advantages, can get pretty much under 3/4 of the length) - my idea of fun - corrosion is fairly light IMO, been at the loose stuff with a wire brush, looking a little better already. In terms of protecting the underside long term, what sort of thing would you recommend ? Waxyoyl ?

Dave81 - first few things I'm doing will be fairly soon, hopefully won't be out of action for long. Things like lighting and steering need sorting out ASAP, can't wait.

Had the same issues when i had the TVR and outriggers. In the early days most were promoting Wayoyl.
What some guys didnt notice is that it has a nasty habit of not only locking moisture out, but also locking moisture in. This ate through them x2 as fast.

A lot opf guys seem to recomend POR15. Though i've never used it the initial reports seem good!

Only what i had read from other owners, not personal experiance, but most of the group were highly regarded in the TVR circle, so have no reason to doubt!

Dave-R · Post by **Dave-R** » Thu Mar 14, 13 8:41 pm

Carl wrote:The great 340 360 debate short strike bigger bore more HP. Smaller bore, longer stroke more torque.

You seem to be totally mistaken about how an engine makes power and what torque and Horsepower are.

Torque is the power an engine makes. Period.

Horsepower is just a way of describing torque in relation to RPM.

The camshaft dictates at what RPM you make torque. NOT the stroke of the engine.

If you make torque at high RPM is is more usable for speed if you have gears. Make torque at low rpm and you need fewer gears but top speed is limited.

Traditionally a low rpm designed engine would be given a long stroke in order to give the piston a higher speed and increase the vacuum signal to the carb.

A high rpm engine already has the high piston speed and so you use a short stroke so that the piston speed is not excessive.

Stroker engines play off higher piston speeds against the gains of having a greater capacity (more air/fuel = more power) but actually work better with single plane intakes and big carbs.

Here endith the lesson.

hjworton · Post by **hjworton** » Thu Mar 14, 13 9:07 pm

I don't understand the technical side of things at all - cars seem so much more complicated than bikes

Dave81; Cheers for the tip, I'll check POR15 out.

mopar_mark · Post by **mopar_mark** » Thu Mar 14, 13 10:16 pm

Dave wrote: Here endith the lesson.

And a very good lesson too

If the 318 is lacking & you have a good offer of a 360, I personally would take the swap.

No point in over complicating, I would also stick with the auto

If your going completely flat out, hi out, high rpm, then yes 340 could be a better deal. Trying to read through the lines, I don't think that's what your after

Pete · Post by **Pete** » Thu Mar 14, 13 11:52 pm

360 and stroke it at a later date (the stroker has a cast crank but I have never heard of one failing).

Or, stick with the 318 and go Big block later and spend your life filling the gas tank and smiling manically......gotta love a 440 (+)

MilesnMiles · Post by **MilesnMiles** » Fri Mar 15, 13 7:09 am

For simplicity it's 360 all the way.
Your engine mounts will already fit
Your exhaust wil already fit
The difference between 318 and 360 really is night and day especially in usable torque
15mpg
Massive and relatively cheap source of tuning parts

Pete · Post by **Pete** » Fri Mar 15, 13 8:27 am

I seem to recall that 1 engine mount is different between the two? Drivers Side? Guy can advise....Still the easiest way forward.........

Dave-R · Post by **Dave-R** » Fri Mar 15, 13 8:42 am

mopar_mark wrote: And a very good lesson too

I have moments of clarity and then it all goes back into the haze...

Pete · Post by **Pete** » Fri Mar 15, 13 8:46 am

I did have an "E" body that ran 12.4 with a 318 and Nitrous.....pretty quick.
Off the bottle it was gutless, though......I stuck a 440 +6 in it and that sorted it out

There are lots of different strokes on how to get what you want.
Often the hard part is deciding what you want.

I want a 500+ ci Stroker that does 30mpg

Dave-R · Post by **Dave-R** » Fri Mar 15, 13 8:55 am

Pete wrote:I did have an "E" body that ran 12.4 with a 318 and Nitrous.....pretty quick.
Off the bottle it was gutless, though......I stuck a 440 +6 in it and that sorted it out

There are lots of different strokes on how to get what you want.
Often the hard part is deciding what you want.

I want a 500+ ci Stroker that does 30mpg

Yeah but it had no roof so that's cheating.

It is possible to have a car with around 400hp and yet get 30mpg. But it is made of plastic and wears a bow tie.

Pete · Post by **Pete** » Fri Mar 15, 13 8:56 am

I quite agree, but you have to be a hiardresser, and that is quite a price to pay

Dave-R · Post by **Dave-R** » Fri Mar 15, 13 9:00 am

Pete wrote:I quite agree, but you have to be a hiardresser, and that is quite a price to pay

I only cut my own hair and my Dads cos he don't get out any more and I get sick of him looking like Jeff Brown.

Pete · Post by **Pete** » Fri Mar 15, 13 9:03 am

I have to be nice to Jeff at the moment...