Final engine teardown and 340 biuldup questions

[torredcuda]

Finished tearing down the 340 and didn`t find any other major problems other than the wiped cam.Main bearings have some pretty bad wear from all the metal going thru them but the crank should be Ok with a polish.So I`ll get out of it with new oil pump,bearings,gaskets and obviously new cam and lifters.Question is should i stick with the Mopar .508 cam or try something else.Engine specs are -
340 .030 over
forged TRW pistons
mildly ported(bowl cleanup/radiused) and gasket matched 915 heads,book says 65cc but we cc`d them at 68.5 poosibly due to tulip valves?
2.02 intake/1.6 exhaust
compression ratio is 9.5:1 .020 above deck with an .05 thick head gasket
1.5:1 ductile iron adj. rockers
750 DP Holley with Proform body
curently have Torker single plane intake but also have an LD340 dual plane

4 spd 3.91 rear in a 3500 Barracuda

would like to get 400-425 hp and run a high 12 if that`s possible with this combo?Any suggestions on cam or other mods?

[matt63]

If you search on the previous posts there has been lots of discussions and recommendations on cams.  I think that the consensus is that more modern grinds are available than with the MP cams.  Personally I am happy with the Hughes hydraulic roller cam I have in my 408.   Others like Lunati, Comp Cams, Hughes, etc. The hydraulic roller cam is not really a budget selection though but you do have the adjustable rockers already.  If you go hydraulic flat tappet I would make sure you get the matching valve springs and pay careful attention to the oil and/or oil additive you use.  Of course your cam/intake manifold combo will be very important as they dicate what type of power range/band you are going to get and must both match.  Good luck!

[1970hemicuda]

High 12's possible, but a lot will depend on your tires.  You'll need to hook up AND have the right diameter to help you stay in your hp band at the end of the track to keep pulling all the way through.  I'm thinking 28" tires with your 3.91s.

[torredcuda]

The old combo of this engine ran 13.26 @ 100mph with the LD340, .480 lift cam and no port work on hard BFG`s  about 26" tall.

[matt63]

I like looking at some of the dyno tests articles to see what other combos made for hp.  Hughes Engines and Comp Cams web sites have these.  In one of the Comp Cams articles (out of a Mopar mag) a 340 made 391 hp with the XE268 cam.
http://www.hughesengines.com/general/techArticleIndex.asp
http://www.compcams.com/Community/Articles/

[KellysCuda aircard]

I would be checkin with CP, but wouldnt 1.6 rockers be a better choice, and also going with as much lift as your heads will allow.

[Chryco Psycho]

as long as the heads flow more with the extra lift yes more lift is good , with stock heads /no porting it will not help , I would use a mechanical cam over a hyd but I have had great results using Engle cams with their hyd grinds , Engle also has some great solids but I tend to use Lunati for the solids as they have some great grinds available

[torredcuda]

I would be checkin with CP, but wouldnt 1.6 rockers be a better choice, and also going with as much lift as your heads will allow.

   And after checking some previuos posts on cam selection I think I could use one with 110 or 112 cl as the .508 had too narrow a powerband with 108.the previous .480 cam was an Engle with 110.I am also considering going to a solid instaed of the hyd.

The heads are ported but I don`t have any flow numbers.They have the bowls blended and smoothed and runners opened out to the gasket.Any guesses on which solid would work?

[Chryco Psycho]

I assume you want to be in the 2000-6200 rpm range , the grinds I would look at would be the Lunati 40499 -TF62 / TF60 - 110
the grind 243*/251* @ .050 , .548/.570 lift with a 2000-6200 powerband

[torredcuda]

I was thinking more around the Mopar .528 112cl cam or an equivolent other brand.Should I stick with a single plane or swap back to a dual plane intake?

[Chryco Psycho]

the LD is one of the best intakes made But I still prefer single plane intakes

[moper]

I would replace the Torker and/or LD340 with an Air Gap. That's a heavy car with mild gears, I think the dual plane that has bigger runners would make decent power and a flat torque curve. For a com, I woudl be looking at a Comp XE275HL for a hydraulic or the XS274S solid. Make sure you have the right valve springs too. Fast rate cams ususally run more spring pressure, and you are much better off running more spring that will stay strong than running at the max rating of your current spring. You will also want to verify two things...Lifter rotation, and the break in procedures are followed to the letter.