What's the factory difference between an HP and non-HP 383?

[bull]

Other than the obvious things like carbs and exhaust manifolds is there that much in the way of internal differences between an HP 383 and a base model 383? I'm talking 2nd gen years here BTW if that makes a difference.

[Nacho-RT74]

camshaft
double valve springs
windage tray

probably pistons ... I know 69 2 bbls 383 are smaller compression rate than 4bbls on same year

[69CoronetRT]

Other than the obvious things like carbs and exhaust manifolds is there that much in the way of internal differences between an HP 383 and a base model 383? I'm talking 2nd gen years here BTW if that makes a difference.

There is a difference in the B body 68-70 hp and non HP variant. (the A body 383HPs have more differences such as dual point distributors)

The exhaust manifolds are the same. What are called HP manifolds are really just a 4bbl manifold. The only other manifold is the 2bbl manifold.

HP's used the same cam and valve springs as the 440HP cars
HP's got a windage tray.

That's why the blocks are stamped HP. The long blocks were different than the non HP cars.

Carbs were different and changed from year to year and application to application. The 2 and 4bbl pistons are different but there's no difference in the HP vs non HP piston.

The only way to ABSOLUTELY confirm which engine the car recieved is via the broadcast sheet or the fender tag on a 69 or 70 Lynch Road built car. Many, many, many sources cite the use of the H VIN code and 62/63 engine tag code as the code for the HP engine which is entirely incorrect! These codes were administrative and sales codes, not build codes. Both codes only indicate a 383-4bbl application not which variant the car recieved.

68 B body 383HP build sheet codes are 760 and 761 (assembly number varies due to automatic vs manual tranny)
69 B body 383HP codes are 925 and 926

[firefighter3931]

Other than the obvious things like carbs and exhaust manifolds is there that much in the way of internal differences between an HP 383 and a base model 383? I'm talking 2nd gen years here BTW if that makes a difference.

By base model are you referring to a 383 2bbl engine ?


Ron

[bull]

Other than the obvious things like carbs and exhaust manifolds is there that much in the way of internal differences between an HP 383 and a base model 383? I'm talking 2nd gen years here BTW if that makes a difference.

By base model are you referring to a 383 2bbl engine ?


Ron

Yes. I don't know if that's the right word to use... I guess a base model would be a 318 or /6 maybe?

[firefighter3931]

Th difference between a 383 2bbl & 383 4bbl is not that much really ;

(1) an extra point of compression
(2) larger cam & better valvesprings
(3) different intake/exhaust manifolds
(4) windage tray

The block, heads, crank, rods were the same



Ron

[Nacho-RT74]

Th difference between a 383 2bbl & 383 4bbl is not that much really ;

(1) an extra point of compression
(2) larger cam & better valvesprings
(3) different intake/exhaust manifolds
(4) windage tray

The block, heads, crank, rods were the same



Ron

so I wasn't wrong .

is the extra point in compression because pistons or what ?

[John_Kunkel]

so I wasn't wrong .

Except for the "double valve springs". 

383-2 pistons have a lower compression height than 383-4.

[69CoronetRT]

Th difference between a 383 2bbl & 383 4bbl is not that much really ;

(1) an extra point of compression
(2) larger cam & better valvesprings
(3) different intake/exhaust manifolds
(4) windage tray

The block, heads, crank, rods were the same



Ron

68-70 383-2bbl and 383 B body 330 horse 4bbl  used the same cam.
B body 383-4bbl HP used the same cam as the 440-4bbl HP.

dlh

[bull]

Th difference between a 383 2bbl & 383 4bbl is not that much really ;

(1) an extra point of compression
(2) larger cam & better valvesprings
(3) different intake/exhaust manifolds
(4) windage tray

The block, heads, crank, rods were the same



Ron

68-70 383-2bbl and 383 B body 330 horse 4bbl used the same cam.
B body 383-4bbl HP used the same cam as the 440-4bbl HP.

dlh

Wait a minute. I thought the 330 horse 383 4bbl was the HP.

[Rolling_Thunder]

depends on the car model...     A body had a 330hp 383...      road runner and charger i believe had a 335hp 383...     same engine...   

[69CoronetRT]

Th difference between a 383 2bbl & 383 4bbl is not that much really ;

(1) an extra point of compression
(2) larger cam & better valvesprings
(3) different intake/exhaust manifolds
(4) windage tray

The block, heads, crank, rods were the same



Ron

68-70 383-2bbl and 383 B body 330 horse 4bbl used the same cam.
B body 383-4bbl HP used the same cam as the 440-4bbl HP.

dlh

Wait a minute. I thought the 330 horse 383 4bbl was the HP.

It gets confusing between 68-70. The 330 horse was considered the HP in 67 and prior and the 300 horse in 71 as there was no other 383-4bbl engine available. During those years, it was called the HP engine but only compared to the 2bbl engine. 4bbl = HP I guess......

Between 68-70, the B body 335 horse 383HP was different than the standard 330 horse 383-4bbl.

The differences are listed above.

The 335 horse was introduced for the 68 Road Runner and Super Bee and was used in 68-70 Super Bees and Road Runners with either tranny but without A/C.

I've also found 69 Chargers, Sport Satellites, Coronets, etc with four speeds and without A/C have the 335 horse engine.

I'll have to check my info again but I think Chris found an example of a 70 Charger with A/C and a four speed with the 335 horse engine. The 335 was not supposed to be available with A/C in 68 and 69 but examples from 1970 may exist. Research continues....

I had a thought as I was typing this post. The only '68 B bodies built at Hamtramck were Chargers. There would be no reason to ship B body 335 horse engines to that plant. The St. Louis plant would have the HP engines on hand for Super Bees and Road Runners. I'm wondering if you could find a late built '68  four speed Charger with the 335 horse engine from the St. Louis plant....   That would be an interesting find.

[Nacho-RT74]

so I wasn't wrong .

Except for the "double valve springs". 

383-2 pistons have a lower compression height than 383-4.

arent they double spring ?

[69CoronetRT]

so I wasn't wrong .

Except for the "double valve springs". 

383-2 pistons have a lower compression height than 383-4.

arent they double spring ?

Technically, I think they are a spring with dampener to go with the HP cam.

[bull]

As I understand it there was only two 383s put in '68 Chargers, the 290 horse 2bbl non-HP (obviously) and the 330 horse 4bbl HP. I don't know about the '69-'70.

[Nacho-RT74]

so I wasn't wrong .

Except for the "double valve springs". 

383-2 pistons have a lower compression height than 383-4.

arent they double spring ?

Technically, I think they are a spring with dampener to go with the HP cam.

well that's what I mean... however I don't know for sure what makes that inner spring or whatever it calls

[ryan053]

so if a 68 charger has a 4 bbl 383 is it an HP?  are there any stampings or anything that will say hp?  i just looked on my car and all it says on the pad by the distributor is d383 and 6 13.

[69CoronetRT]

so if a 68 charger has a 4 bbl 383 is it an HP?  are there any stampings or anything that will say hp?  i just looked on my car and all it says on the pad by the distributor is d383 and 6 13.

No. It would be highly unlikley a 68 Charger had an HP engine.

An HP engine will be stamped with the letters HP on the pad. No HP = 330 horse.

In my opinion, and it is only my opinion, the only way a '68 Charger could have the HP engine is IF it was built at the St. Louis Plant and IF it was a manual tranny. Proving it would be very difficult. You would have to do it via the broadcast sheet. The number if IFs in this scenario cut down the probablility it could be verified.

[69CoronetRT]

As I understand it there was only two 383s put in '68 Chargers, the 290 horse 2bbl non-HP (obviously) and the 330 horse 4bbl HP. I don't know about the '69-'70.

Due to the RR/SB variant, the 330 horse is not considered the HP engine from 68-70. The 335 horse is the HP version. The A body GTS used basically the same 335 horse engine as the Super Bee except it was downrated to 300 due to the more restrictive exhaust manifolds.

[JoeyGowdy]

I've been looking for the HP stats - many thanks for posting them.