383 BuildUp

[68GrayJ]

Hello,

I have my 383 apart, and cleaning up the parts a bit, and planning out some details. I had a couple questions for ya.

For valve guides, do you recommend upgrading to bronze? If so, where do buy them?

Also, I am looking at cams, and I was wondering what the limit typically is for lift, before cutouts are required? I just don't want to order a high lift cam that wont work with the dished pistons.

I am trying to stay around 9.5 to 1, because I was entertaining the idea of a procharger.

I heard good things about the whiplash, but the engine I am working with is the 2 barrel '68 383, and they're advertised for low comp ration engines. Ive also heard good things about the 484 mopar cam, but understandably its fairly old, and there are better cams out there. Recommendations?

Ive got the list for machine work already this far:
Guides, Port Work, Mill .030 Heads (906's), Hardened Exh Seats
.010 off deck

Overall goal is around 400HP N/A

[DavidPope]

A decent cam and heads and headers with a Performer RPM intake will get over 400hp.

[MadMC63]

The 284/ 484 @ 110 center line are very choppy cams. Lots of giggling around while in gear at red lights and such.

[Kaegi]

I have a 361 from medium duty truck in my d300. i saw in manual that the heads have hardened valve seats, and sodium filled exhaust valves. I don't know if they are larger cc than the car heads but with with flat top pistons I bet comp ratio would be 9 or so. might be less expensive to find a set of those heads rather than have seats put in yours. I think i am going to swap cam and flat top pistons in my 361. the stock pistons put it at 7.5 to 1. works good towing but no faster than a poly on the flats.

[slick]

I have closed chamber 915 heads on mine. They are polished and gasket matched, bigger exhaust valves. I also have the mopar 484 purple cam. It's a decent motor, but I wish I would have went bigger on the cam. It has a decent lope, but nothing crazy. My dad has the 509 cam in his 440 and I really like that cam.

[DavidPope]

Those truck heads are a bad choice. Around 7 to 1 compression, and poor flow.

[twayne24365]

With the stock small dished 383 pistons we ran a 528 mopar solid cam, stock heads with headers, Street dominator intake, and Holley 850, motor came in at a whopping 8.5:1 compression and ran 12.50 in a 65 coronet.

I’d be Leary if the 509 cam, It doesnt produce much vaccum and would be down on low rpm torque. I would look for a more modern lobe profile with a little less duration and overlap if you want to stay with a hydraulic cam

[MadMC63]

I agree with twayne24365. The bigger the cam the less the vacuum and the higher the RPM to get into the power band. Plus the bigger the cam the more the need increases for a manual trans or stall converter. I know MP sales the 284/284 484/484 witch really is choppy and the 508 or 509 is worse and both are at 110 centerline. I used a comp cam 280/280 480/480 on 112 centerline and was surprise that in gear it didn’t sound like much more than stock, pretty smooth idle. Excellent vacuum and drivability characteristics. As soon as it was in neutral or rolling at idle it sounded kind of hot.

[MadMC63]

The 292/292 509/509 works very well and definitly sounds hot. It also shakes the entire vehicle and is best suited for a manual trans. When I ran it I had 4:10's in the rear with 26" tall tires and it wasnt enough. The article/ car I based that engine on ran 11:20s and had a 4:30 rear end.