Need help asap 340

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Hoophoop

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Anyone,
Please help me make a decision, I have a 73 duster 340 4 speed with 3.90 gears, I have some engine issues..pushrods came up through rockers on number 2 and number 8, the engine was just rebuilt 200 miles ago....I assume I have stuck lifters and prob wiped out the new comp cam also...her is my dilema, I have 10K to drop into engine (wife give me green light) what would you do assuming the low end is still good shape, heads,headers,supercharger or stroke it to 416, or just top end kit with cam heads and up the carb? PLEASE ANY SUGGESTIONS WOULD BE GREATLY APPRECIATED, IF ANYONE DOESNT WANT TO TYPE...pm ME AND i WILL GIVE YOU A CALL!!
 
I agree. High spring pressures and stock rockers don't mix well.
 
im running comp ultra pro magnum roller rockers on my 360 with a good sized solid roller so they handle the extra spring pressures. If the engine was just rebuilt before I wouldn't touch the bottom end, but I would figure out why the problems occurred. Other than that I'd change out the cam and top end like you said. You could do a supercharger but that's dependent on if the bottom end could take it. So ring gaps correct and so on.
 
pulling off intake this morning and looking, but still want to put some money in it...i want some more horse..i'm guessing im in the 325-335 hp range now...would like around 450-500
 
who sells a good stroker kit with heads, like a package deal?
 
depends who rebuilt it....if YOU rebuilt it, take the 10 grand and send the engine to a reputable builder and have them do a stroker.....if it WASN'T you, then find a different builder (or do it yourself if you know more than the builder)....if it was rebuilt just 200 miles ago and you have pushrods coming thru = somebody messed up and they shouldn't be allowed near an engine....
 
i think it's 468 lift not sure i didnt see the card on it, i just bought the car 3 weeks ago, work was done before i bought it
 
it was supposed to be a reputable builder...Ross automotive in Flushi ng Ohio, I talked to him on the phone yesterday...and he wasnt to compelled to answer anything.
 
Thats why its better if you have the time and are willing to learn to do your own work. Every time I look at farming something out I realize what they are going to do and just do it myself. 10K is A LOT of money to spend on a small block. But, I don't know how much a machine shop charges to build motors so it might be as much as I think. If it was me and I only wanted 450ish I would but some heads (new rockers too) on it with a cam and call it a day.
 
Hoophoop said:
i think it's 468 lift not sure i didnt see the card on it, i just bought the car 3 weeks ago, work was done before i bought it
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Then stock rockers should be ok with that set-up. Were the rockers new or used when they built the engine? Maybe think of a new set or get the adjustable ones.
 
Hoophoop said:
it was supposed to be a reputable builder...Ross automotive in Flushi ng Ohio, I talked to him on the phone yesterday...and he wasnt to compelled to answer anything.
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Yeah, because he's in "damage control" mode... #-o

(To limit the amount of HIS damages...)
 
A lot of guys like to build their own, and I give them lots of props for that. I am not experienced enough to build my own. So for me, if I had $10,000 and could do it all over again, I would send your parts to MRL performance or Indy Cylinder Head and have them build you a badass 360 or 408 stroker making 450-550hp. There are several other places that could do this as well. I had a guy try and build me a 360 and he screwed it up, so I sent the block and heads distributor to INDY and they tore it all down, started over, built it to their specs, and i ended up with a 425hp/405ft lbs and it is running great. They broke it in, send it in a crate, ready to drop in about 2 weeks. I wont say they have the best "bed side manor" but they are obviously good at what they do. Hope this helps.
 
The rockers may have been well worn before and they were pushed to their finish by a bit more stress. My concern would be that weak/worn parts like this are also in the bottom end.

For minimal $$, I wold try to check out the bottom end, and redo the top. But to know the bottom end is right, it HAS to come apart and be thoroughly measured, all parts checked. Basically, starting over is the only way I would approach this; back when I was young and poor; I would take a chance on the bottom end. The bottom end may well be perfect, but there is no way of knowing this at this point. And you don't know how it might have been abused by the prior owner.

$10K is a LOT in my world; my son and I just built a 340 from scratch at 375-400 HP (supposedly) for a bit over $5k with goods heads (Edelbrocks); all we had was a crank, oil pan, headers, and timing cover to start with LOL. So all else was bought. But we did all the checking and assembly and just used machinists for that work. I am guessing you are not as experienced a builder, and so going to someone good with your pile of parts may be the best bet. I cannot make a direct endorsement of MRL (As I do not know them personally nor even have had them do work) but he seems to enjoy a good reputation here, and is close to you, up in MI. There are also a couple of older, good builders in the Toledo area; both have built serious drag race engines for years. PM me if you want numbers.

450 500 HP... how did you come by that number? 350-400 HP is easy in this day and age. 500 is more work and more serious parts. What are the intended uses for this car? Drag racing? Cruising? ALWAYS start with the intended use and then build the engine to that, NOT to some good sounding HP number. I ask because all to many new folks think that 500 HP is needed for some reason...but 350-400 HP can be a TON O' FUN on the street if built in the right way and is significantly less costly.
 
it may not be as bad as you think, maybe, i did the same thing last year,punched through 2 rockers and blew a head gasket. metal pieces were sitting on top of head, replaced what i had to and so far so good.then again if i had 10 g's to spend i would surely be tempted!!!
 
Hoophoop said:
i think it's 468 lift not sure i didnt see the card on it, i just bought the car 3 weeks ago, work was done before i bought it
Click to expand...

Thats a little cam..certainly shouldn't be breaking through rockers...something is wrong somewhere..
 
Make sure you do it right, you may not have 10k next time, no matter how cool your wife is!!
 
I've seen quite a few engines with pushrods thru rockers with no engine damage, I used to carry a coupla spares in my trunk, just in case. I occassionally popped one if I missed a shift.. Mopar came out with a heavier duty stamped rocker to help solve the prob.

I'd just replace the rockers affected, check that the pushrod's straight. (roll it across a flat surface) and look for a set of H/D stamped rockers.

It kinda sounds like you wanna spend money, but this'll likely get you going for now..
 
Had a push rod go threw 1 stamped rocker,bent the other 1,took friends for spin trying to blow the motor running on 7 cylinders..lol Tore engine down,crank had cap walk.part of dip stick,welding slag,crank key in pan.Motor was also suppose to be done.Only thing I kept was the block.New stroker 419 now with my engine builder.Nite and day.450 to 500 hp to easy,with strokers.It's all the power I want.10 grand ,get her done and enjoy.360 works the same.
 
stroked340 said:
Thats a little cam..certainly shouldn't be breaking through rockers...something is wrong somewhere..
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I've seen a couple of cars with cam in that lift range wipe out stock rockers due to high valve spring pressures.

Stock rockers don't like dual valve springs...
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