Warmed over 318 rebuild now 390 stroker project cam advice needed.

[popinsmoke]

Gentlemen,

In another post I showed the carnage from the broken crank on my 318 nested in between the fenders of my 67 coronet 440, I had always planned on running a stroker just had not planned on it being sooner then later.

The 318 is setup now with a stock bottom end and stock bore (going .30 over)

New bottom end is the hughes 390 kit.

Top end is, RHS LAX headed mild port and bowl work, MP electronic ignition, Performer rpm air gap intake, 750 carter afb (was planning the stroker the whole time)

Comp cams 268XE, hughes rollers rockers, TTI step headers, 727 full manual valve body with a 3000rpm stall.

Backed by a 8 3/4 sure grip 4.56 gears (local track is 1/8 mile.) Compression with my heads and the pistons in the kit should be 10 to 1 or 10.5 to 1

Any advice on what cam to run?

I know that the 268Ex was a great cam for the 318 (it did want more compression) but I feel I will be leaving quite a bit on the table if I leave it in.

 

[popinsmoke]

Ok a lot views and no replies I am leaning towards the Comp Cams XE275HL anyone running this cam or have any opinions?

 

[Cevidicus]

I bet you'd get way more comments if you posted this over at FABO in the small block section. Tons more small block guys there. Good luck.

 

[Meep-Meep]

The very basic advice I can offer is choose first based on LSA. A tight LSA like 108 will produce more peak torque at a higher RPM and that sounds like what you are after. And that should take your compression ratio, basic bottom end RPM limit and heads into account - plus many more things about the car.

 

[Rich Kinsley]

I have recently joined this group and I also live in Omaha near 139/Harrison area. I have a 318 poly in my '64 Dodge so it's a different bird than your LA. However I can give you a lead on a superior Mopar machinist who lives in Gretna. He does some nice work at his home shop on his days off. It's Randy Beyer Racing Engines

[email protected] 402-658-9888

He is a super nice guy and can tell you all you want to know. He can also supply parts if you so desire.

I know from my personal experience on my build I ran 2X4's on my .040" over poly with a 264deg cam with 111 deg sep. I later switched to a 284deg cam with 106 deg sep.. My rpm's went from 6500 to 7500 with the bigger cam. The engine ran better and cooler and I dropped 6/10ths sec off my 1/8th mile time without even tuning it! Going too conservative with the cam was a detriment. And yes I did have the other components required such as gears, headers, stall converter, ign, etc..

 

[Supershafts]

I know that the 268Ex was a great cam for the 318 (it did want more compression) but I feel I will be leaving quite a bit on the table if I leave it in.

You are leaving a lot, and even the heads and intake, and the stall..... you look like you're building a 318 still, and you aren't.

You want to revisit what you're doing with heads and that head, indy/brodi/edel vs mild porting? lots of porting, air gap? m1 or victor

 

[popinsmoke]

The heads will be getting bigger valves and full port and bowl work, they are aftermarket RHS LA-X heads. I know that there are better heads out there but I got the ones I have for next to nothing in a horse trade. I have not heard anything but positive reviews on the edelbrock performer rpm air gap manifold, as for the carb I would think the 750cfm would be enough for a 390 CID engine.

Compression is going to play allot into factoring the cam choice I am not going to chose anything that is going to come on after 3000rpm so I think that to 3000rpm stall should be plenty.

I am shooting for 1hp to 1.5 hp per CID I think I should be able to hit my mark, but then again I have been wrong before.

 

[Supershafts]

I'd look in the 240/250@50 550 lift area and 110/108. I'd also use the M-1 intake and do more porting to the heads.

 

[69coronet4door]

I'm going a different route than the normal... I like to be "unique" ...I got 1969 with 318 and I'm planning on going turbo with it. 2 of the HT-35 that produce 18lbs. each... got 340 heads for the extra travel, using Summit 290/480 combo on the cam.. all run through a stock thermoquad that has been tweaked to match 1050 Holley...

after done.. should be near 600hp. not bad for a 4 door..