For starters,

I'm new to this forum and this is my first post XD

I was wondering if it is at all possible to get close to 300 hp out of my 3.7 litre 225 Slant 6.

but heres the catch

without boring it and keeping it N/A.

feedback much appreciated.

p.s im from oz

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Shazzam66

'Valerie' 1966 Chrysler Valiant VC with 3.7 litre 225 Slant 6 backed by A904 3 speed Torqueflite

If your budget doesn't include boring the block your budget cannot include what you do need to make 250hp let alone 300. If you're excluding nitrous the answer is no, you will not be able to achieve 300hp NA with such a budget.

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Joshua

NA? Net?

How do you feel about nitrous?



CJ

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Part of Tyrde-Browne Racing

no giggle gas for me thanks

i never mentioned anything about budget

i would even be happy if i got 1hp for every 1 cubic inch

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Shazzam66

'Valerie' 1966 Chrysler Valiant VC with 3.7 litre 225 Slant 6 backed by A904 3 speed Torqueflite

You may not have said budget, but a low budget the only reason to keep using worn out-of-round cylinders and old pistons. You're going to need to be explicit on what you want from the car as far as ET or driveability and your budget. Do you want that 225hp at the wheels?

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Joshua

i'm building a 300 horse slant to but i cant tell yall whats in it or i would have to shoot all of yall (i keep my builds under lock and key)

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six

okay forget the word BUDGET.

but i will take your advice on being explicit and specific as to what i want:

- I want my slant to being pushing as close to 300hp as i can get without: nitrous, super charging, turbo charging or EFIing or boring, just flat N/A

- I would like it to be a real V8 killer, david and goliath type stuff.

- I would like great streetability but for it to get up and really gallop when i push the pedal down.

and theslantingsix why even post if you can't offer me any advice, lol...

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Shazzam66

'Valerie' 1966 Chrysler Valiant VC with 3.7 litre 225 Slant 6 backed by A904 3 speed Torqueflite

You will have to get your flow numbers up to 240/230 just to start. There is a lot of gain to be made in the head. I dont think it is realistic to get 300HP out of a Non bored slant. It will be hard enough to get it with a power adder.
Have FUN and try,
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

Big compression, race gas, E-85 or alcohol, strip cam, very high stall converter, your going to need something special for induction and good headers. To get the primaries opened up enough you'll likely need to make your own. Oversized valves, electric fuel and water pump. Something evil for an ignition system. Lot's of care selecting parts.
300 hp naturally aspirated? A built 340 of like investment will still leave you in the dust.

A realistic expectation would be 250 crank hp, but it will have to be done right. An overbore would be helpful, if only to square the engine up a bit for a bit higher theoretical redline.

Use the search engine. This question gets asked a lot. Arbitrarily grabbing a number isn't the way to start a build.
Depends on what you mean by steetable. I'd say, no. Can't do it with a streetable car.

CJ

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Part of Tyrde-Browne Racing

rather then everyone telling me its unrealistic, could i please have some tips or some comparisons of options

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Shazzam66

'Valerie' 1966 Chrysler Valiant VC with 3.7 litre 225 Slant 6 backed by A904 3 speed Torqueflite

I feel for you but you have gotten some good sugestions. I would start with this info and get a plan together. Crunch some numbers thru an on line calcutator and see where your at.
Just a thought. Then come back with a specfic set of questions.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

There are no tips, because there is no way you can get what you want. If you want a V-8 killer with street manners, power adder is a must. Also there is absolutly no sense trying to build an engine like you are asking for, without boring to get the cylinders round and true, for a good ring seal. To make big power numbers, you must start with a good basic short block, that seals the compression. You are starting out with a cubic inch disadvantage to the V-8s, and an RPM disadvantage to the imports. So why handicap yourself further with cylinders that will not seal. You will need round and straight holes, light piston and rod assy, and the best ring package available. Then go from there.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Rather than focusing on HP, can you tell us what 1/4 mile time you would like to achieve, and how much your car will weigh or what kind of car?

Most people think you need 300 HP to do 14 sec 1/4 miles, but that is far away from the truth. 230 HP can get you to the 14s, which is doable with a streetable (but a bit radical) NA Slant and a fairly light car.

Thanks,

Lou

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Home of Slant6-powered fun machines since 1988

300hp will take lots of time and $$$.

Without a power adder, the streetability wont be there- In my opinion.

The 300hp mark will take about every modification you can do to your /6, and that will include boring it. You want a round/true cylinder bore to make max power. When you bore it, the rings do tend seal to the walls better with a smaller overbore (example- say .030 over vs. 040 or whatever is desired). It's the old, more cubic inches vs.rigidity debate.


It's gonna take compression as well. Lots of it. You might wanna consider
running alky to meet your desired hp

Lou (Dart270) makes a good point. Get the vehicle as light as possible to get the most out of it!

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Michael Glass. Mopar stuff and some rusty Mopar stuff!
1965 Dodge Dart with 66 Valiant front clip. Other stuff...

check out my cardomain for some ideas (pages 3&4) i was just messin with you. i'm going for the erson 270 cam which will be degreed, major back yard port and polish, in 1.77, ex 1.44 valves , .100 off the head .30 over, underdrive pulleys (check out jegs under march pullys and use the small block water pump pully), eletric fan, offy intake, holley 390, clifford headers, (at this point i want to be pushing 300hp) and after that a shot of nos.

and the budget always goes away my budget on this engine was gone $1000 dollars ago, and i'm going to spend more

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1973 plymouth duster 225 slant six .30 over, erson 270 cam, 9.5 to 1 compression, big valves, headers, and a holley 4 bbl
http://cardomain.com/ride/3135091

hey that thing got a hemi? naw its just a slant six