Box Stock

Here's what I'm doing what do you think?

S

Suffuuk83

New member
So I purchased a hemi to replace a 8hp Briggs that I ran for 10 years on alcohol. The goal is a high hp motor but look stock as possible I'll be running a run what you bring type of race. So here's my plan for the hemi
1. since my piston is in the hole .028, I'm going to get the .040 billet rod and cut .012 off the piston for 0 deck height
2. I'm thinking of shaving the head between .030 to .050
3. My black mamba cam is on the way, I'll be running 26 pound springs I'm still trying to figure out retainers any suggestions will be appropriated I want to run stock valves but update retainers etc
4. I will be running a Chinese 13 hp carb with a air filter kit
5. I think I'll have to run a mix of premium and 110 luckily a gas station sells cam 2 110 by the track
Any suggestions and thoughts will be appreciated thanks guys
 
Before you decide on the fuel to run, be sure to check the CC's in the combustion chamber and calculate a compression ratio.
 
I'm not seeing what you are attempting to accomplish. In a "run what ya' brung" no small block clone has a
chance .... unless the class is run with small blocks only and other stringent restrictions apply.
 
It's a small block heavy class Hondas, clones, and predators "stock" appearing so no tilys and other carbs that's why I'm using a 13 hp which is what everyone is using no fuel restrictions including using pumps and throttle plates must run slicks no weight added to the chassis to help setup, drivers top of helment must be no less then 14" from the ground but can be higher that's about the all that I can think of right now
 
Call Barry Young (Youngengines) and talk to him. IMO, the hemi head is not the way to go. It can be made to flow very well but compression is lacking due to the huge chamber. Most do a bunch of welding up of the head to make up for this. Again IMO, go with an RT-6 head (or similar). With the horsepower per dollar spent formula you would be ahead. But like I said, call Barry, he has done a lot of "predator" work.
 
jsstump has a good point, I welded my hemi head but most don't have the means to do this. The non Hemi head on the hemi block will give you the compression ratio you want in a bolt on format.
 
Well the nice thing is it can be measured and the head gasket thickness adjusted to compensate. You don't really know until you get everything apart on the bench and cc the chamber, piston dish-if applicable, and the distance in the hole the piston is. At this point, is when I order my rod at the optimum length and head gaskets at the correct thickness.
 
You can make power with a non-welded hemi head, but you will need it milled a fair amount.. and most likely need valve reliefs cut in the piston.. If you don't have the ability to cut valve reliefs (or have them cut), or have the chamber welded.. I recommend a different head.. JMO
 
I never wanted to drop the hemi head, I think it will get me where I want to go plus I'm on a budget by the wife. Anyway I have access to a milling machine and lathe I'm planning to cut 12 tho off the top of the piston (see first post for reason) valve reliefs shouldnt be an issue. Right now I'm more worried about retainers and keepers for the stock valves and 26 pound springs. ANY MORE SUGGESTIONS ARE GREATLY APPRECIATED
 
I have a set of retainers and locks in one of my heads with stock valves. These retainers are black and I'm not sure who makes them, I got them from an engine builder who's a friend of mine. The locks are made to work with the stock retainer groove in the stock valves. I paid $20 for them. I think NR Racing might sell them, or ISKY. You wanna make sure the retainers you get have locks designed to use with stock valves. Listen to Youngengines when it comes to these engines, Barry knows them well and knows their limits/faults, and what makes power with them
 
A suggestion I might make, if I may... Instead of buying a rod that puts your piston out of the hole and then milling the piston (which will thin the top), maybe leave the rod length stock. Mill your head .050-.070". Then mock up with your pick of cam and my 1.2 billet rockers ( oops, did I say that?!?) and see where you're at on piston to valve clearance. More than likely you will need eyebrows in the piston, so having the extra material on the top of the piston will allow you to cut them as deep as you need to. If you have some room to play with, you could deck the block to get to zero, which is more complicated, but if you have a machine then it would be the better way to go in my opinion.
I'm gonna have to give Barry some props as well. He does excellent work. If you need any help with parts he is a good person to talk to. As far as valves, you can get the extended length valves from NR, Barry probably has them too, or when you order my rockers (shoot I did it again) I can hook you up with a set that are drop in for your head, needing only to be lapped in. Or if I may suggest stepping up to a 28.5 mm valve on the intake to keep up with the big alcohol 390 carb (Barry has the best ones) to be able to breathe a little better. That would require a quick valve job and then you could port it yourself to get flow well above what an off the shelf 32mm clone head will do. The after market valves and retainers will cost you around $50-60, but would be a sound investment for a modified engine with a big 390 carb... Which should make gobs of power.
 
I'm a fan of using the thin .009" MLS head gasket, and having the piston in the hole ~.020" to get the clearance.
 
I'm going to use the .009 and shave the head to the absolute most I can before contact with the piston I'm still have crappy luck find retainers and keepers
 
BradH, young, or sneaks should know where to get those retainers and locks. I'm leary of using any of the stock Chinese parts personally, I'd ream the guides to 5.5mm and get some aftermarket valves.
 
The Hemi already has 5.5 mm stems. OP, get some stainless valves. It's not worth using the stock valves. Imo
 
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