Joined: Mon Jun 11 2007, 04:05PM
Location: Marietta
Posts: 37
Just curious, the 383 4V engine that is in my 67 newport is original equipment, is that the same 383 4V engine used in the chargers and such? Does it have the same heads, carb, intake, cam, etc? Im looking at hopping it up some and just wondered what I am starting out with. There's not much info on these cars on the web. Thanks
Joined: Sun Feb 05 2006, 11:51PM
Location: Pa
Posts: 3064
The 383 4V in my 66 300 is only 5hp shy of my 69 Roadrunner engine....330hp vs 335hp. The supposed differences were (according to Mopar) "440" heads (which were the same as 383's), hotter camshaft, a windage tray, and the hi-po exhaust manifolds (which were much better than the 66's log type) with dual exhaust. Seems like all that should be worth more than 5hp
No wonder the NHRA factored the RR horsepower higher than the factory..... <span class='smallblacktext'>[ Edited Thu Jun 21 2007, 11:45PM ]</span>
Canadian versions in 66 were rated 335hp, and were exactly the same motor as your 66 rated at 330. Sometimes I think they had other reasons for making the numbers different.
Joined: Sat Jun 16 2007, 01:18AM
Location: Grand Rapids, MI
Posts: 839
I'm gonna disagree on the heads...
'66/67 383's should have the 516 heads...close chamber 2.08/1.60 valves...
'67 440's should the 915's...2.08/1.74 I/E also close chamber...
'68+ Ma switched all the BB heads to the open chamber 906's...
Intake was redesigned for '68 and the Magnum cam was introduced...toss in the good manifolds as well...Holleys also started to be come fairly prevalent on the HP motors...
For the record my '67 SuperCommando 383 was only rated 325...
Joined: Tue Jun 05 2007, 01:44PM
Location: Minnesota
Posts: 131
It was my understanding that only engines in 68 that had Holleys were the non-HP 440s and the 440 6-packs. For the rest of the 4-BBL engines, they switched from AFB's to AVS's in 68, except for the Hemi, which stuck with dual AFB's. 2-BBL engines also had Carters. However, never say never with Mopar.
Anyway, you are probably correct in assuming that all those upgrades to the Road Runner/Super Bee 383 in 68 are good for more than an extra 5HP. It is well known that the 426 Hemi was grossly underrated at 425HP. The same is most likely true about the 383 Magnum engine. It was probably rated at just 335HP in attempt to "hide" the true power from the unsuspecting. Keep in mind, the Magnum cam was the only difference between the non-HP and HP versions of the 440, and that got the HP one a 25HP boost. Granted, there was also a difference in the exhaust manifolds, but still. And the 375HP was also probably underrated, seeing as how some people will tell you that a properly-tuned 440 Magnum can keep up with a Hemi pretty good. It's just one big number game. <span class='smallblacktext'>[ Edited Sat Jun 23 2007, 01:43AM ]</span>