this is my first post and our first engine build. we have an older 460 thats been bored and stroked to a 514. (at least thats what we were told). we scored a set of 429 cobra jet heads, DOOE-R. is there anything i need to do to the block to accept these heads. any other tips, info, or pointers on cam, lifters, etc. We would like to have roller cam and rockers. like I said we will be pulling and hope to turn around 7000 rpms. Thanks

 

Turning a bb to 7000 is one thing, but without dyno figures who knows if it is making max hp/torque there ? If you want to be in that rpm range and rules will allow it I'd get some better aluminum heads. I'd also make sure to check class rules before buying anything.

 

I agree with class rules... I won 4 years in a row at the nats in amature class.

You need to know what the heads flow to. I agree with rollar rockers and cam. But you need to know what the bottom end is to. That holds alot of torque.

RPMS for pulling are based on many thing, and high rpms alone wont get it. Traction is key. Alotta guys coming out of the gate at 9 grand slipping the clutch. It is freaky to watch up close.

Gearing, tires size also. Have the facts, no guessing

 

in the class i pull in, you arent allowed to have aluminum heads so we figured the cobra jet heads would be pretty good for cast iron. the reason i say around 7000 r's is because right now it tends to float the lifters at 6200-6500. we have 4.56 gears right now but have the possibility to go to 4.11. we also have to run DOT approved tires right now 33x12.50 bf goodrich mud terrains.

 

Lifters float because of weak valve springs. Make sure you flow the heads

 

Leave the gears and go with 35's TSL super swamp boggers. Dick Thornbird also has a good selection. I think the BFG's are nice but not for competion. However I am a BFG fan. I had the TSL's and man they dig.
Interco Makes them www.intercotire.com

 

I run a 466 in the superstock class i have a borg warner t19 with 4.10 gears i run super cobra jets with 2.19 valves and a comp cams solid lifter cam .642 lift 276 degrees at .50 I use 112 octane fuel and msd ignition up top is a 460 super victor and a proform 950 cfm carb
I prefer superswamper boggers in northern vermont but it really depends on the surface your pulling on, my heads flow 325 cfm and this combo consistently turns 7500 rpm under load at about 37 mph wheelspeed if you have to run cast iron heads you have made an excellent find in those old cobra jets hold onto them. The boggers are a dot tire

 

no mods to the block are necessary... theyll bolt on and work. i dont know what your rules are but if porting is allowed id send them to www.reincarnation-automotive.com and have scott port them. proper port work is one of the keys to making good power, and its easier to hurt flow than to help it if you dont know what youre doing. those heads are capable of supporting 850hp when worked properly. id verify the rotating assembly and compression ratio and work from there on the cam/valvetrane parts selection. jmo

darrin

 

If I'm not mistaken, I thought 429 SCJ heads had 2.25 intake valves ?

 

Not 100 % sure about the originals Mark but my heads are the Jon Kasse scj aluminum heads designed for Ford Motorsport and they do have 2.19 intake valves.

 

Don't forget pushrod flex.If you have CJ heads, they should be adequate for flow when pulling. If your ports become too large from porting, your velocity slows and power potential is not reached. Scott will get those done for you nicely if you can go that route. Remember when thinking about making power & torque, its NOT ONLY about Cubic Feet per Minute but Pounds Per Minute or A/F charge. You can have all the cfm you can get with less dense air and it won't produce the needed or wanted output as a more dense, cooler charge. I have never seen these Cobra jet heads before, but I am thinking these are closed chamber, correct??? Then you have to think about setting up your Squish & Quench attributes correctly for efficient combustion. Quench gap (between the piston top & cylinder head - includes gasket thickness) generally between .038 - .040", depends on your app. For example if you have a deck height of say .020" you need minimum addition of .018" to work correctly. Here is an equation for you in determining carb requirement -> Rpm x CID / 3456 x 1.1. Since you want to turn 7000rpms, your calculation for cfm needed (with 514 cubes) is 1145cfm theoretically required. Now what else should you think about??? Keeping the oil away from the crankshaft counter-weights, amount of current valve shrouding, backcutting valves, top cutting or radiusing the valves, maybe shine up the combustion chamber to reduce the heat absorption of the head to make your engine more heat efficient. Selecting the correct camshaft for this application. Having correct valve angles & throat size. Sizing your exhaust correctly. Air charge temp, proper fuel temp, induction style, air cleaner material, compression - dynamic & static, octane rating needed. Bearing clearances, oil type & viscosity........... just to name a few other than your basic cleaning & prep.

 

I just thought you had iron SCJ heads.

 

Yes the D0OE-R heads will bolt right up to the block. However, if your rules allow it, and you can swing it, I highly recommend the EX514 heads. They are capable of more power than the CJ's are. Now that said I know for fact that the D0OE-R heads can support 900 hp, but it takes a lot of cash to get them there. And definitely go with roller lifters and full roller rockers, also balance the rotating assembly. My CJ heads are capable of going way north of 8000rpm, so build your bottom end strong!

Tell me where you are pulling? I ask this because the advice above about tires is simply not applicable in most parts of the country. Real aggressive tires are actually cause problems. The dominate DOT tires are BFG AT's and Super swamper TRXUS STS (these are starting to become the dominate tire).

Let me know if I can help any further.

Alan
Horsin' Around Pulling Team
www.horsinaroundpulling.com

 

we are pulling in southern indiana. most of the guys in our class are pulling with the BFG AT's.
385series hemi, thanks for the info about CFM. that will help in deciding on a carb.

 

No problem, just don't over carb it. Make sure you have the correct booster in the carb too, because the booster signal can make a large difference in an engine performance. Being either sluggish or on target. If you plan on putting mufflers on it, go with Walker exhaust's performance line Dyno-max I think it is named. They rate their mufflers in CFM. When buying, remember how much HP your engine produces because you need 2.2cfm per 1 horsepower to flow exhaust efficiently to make power.