565, 598 or 632 Which to build?

[peachesracing]

I am in the brainstorming process of wanting to build something bigger. My little 498 is tired and wore out. It was kind of a max effort deal. The class I used to race required a stock block and iron heads. I want to start with a new dart, merlin, or even a brodix block.
I want to hopefully use my heads and intake for now. The heads are EQ/RHS 360s cast iron that have some porting done, but haven't been flowed since ported. they were flowed out of the box at 380 @ .800. So I think they surly would do 400 at .800. Have 2.3 titanium intakes and manley springs good to .850. My reasoning for wanting to reuse if possible is because they were new at the beginning of this year. I know they are heavy and probably not ideal but I can't afford new ones if I do a short block.

My first thought was to do a 565 in a tall deck and use my heads. Then I would at least have a block if I decide to go the 632 route in the future.

Could these heads even support a 565 or 600 inches?
Is 950 hp even doable with such a combo? I have a Team G intake and a 2in HVH spacer with a prosystems 1150 dominator.
Im thinking 13.5-14 compression? I've always ran VP113 but was thinking of going to Q16

Any input will be appreciated, Thank you

[tt 383]

If not apposed to the td that's what I start with...

[fdicrasto]

Just a thought, Shafiroff Racing has a 632" short deck short block that they offer.

[Walter R. Malik]

Choose an engine which has the stroke to accommodate whatever mean piston speed you think you should have at the maximum RPM you wish to run ...that will probably make you the most satisfied.

[Ted Gerstenslager]

Cylinder head/valve size will have a direct effect on rpm.
Smaller head on larger cubes will make power lower. Engine will run out of airflow.
I would build the 598. Depending on head, it should peak 6800-7200

[Newold1]

I'll throw in my two cents for what its worth.

Start with a tall deck and that will help keep CH within reason for controllable piston speeds and keep piston rock with associated ring seal and wear and still allow you to run the newer narrow 1.5mm,1.5mm, 3.0mm ring types.
Use a good forged crank and stroke that will allow with associated bore increases in the future to continue the build up to more cubes. 4.375"-4.500".
Compression ratio is easier to raise with bigger inches but you will have to be a little careful with iron heads and ignition advance to keep detonation at bay. Don't skimp on rods so invest now in some high quality, strong affordable rods like Molnar or a few others. With your heads I would say 565 is a good place to start and holding static compression to 10.5 to 11.0 to 1 will be controllable with pump gas and higher numbers are doable with race fuels or E85. Your camshaft design and choice while paying attention to the dynamic compression ratio will be critical to make a good package here.

Reaching 850-900HP with a good 565/iron head engine is doable with the a decent intake system and with future cubes,head and camshaft changes the ultimate build can get you easily over 1000 ponies. This type of build should give you with just bore and piston changes future cubic inches with a strong short block capable of the additional power and rpms you may want in the future.

Just put a lot of quality machining, assembly and parts into the rotating assembly and the short block build as that is where the long term reliable base will come from. You also might want to think about doing the cost now of upgrading the block for .903 lifters and using the newer bushed roller lifters will keep those pesky little needles from destroying your new expensive block investment. Make sure you invest in a good oil system with a good oil control pan with proper windage control. As I always get back to,"build it once right, so you don't have to build it twice!"

[Frankshaft]

How about a 582? In a short deck. Otherwise I would do a 598. The heads you have should support over 900 hp fairly easy. The intake you have needs to go however. Super Victor 2927 is a good intake for the heads you have. I would max the compression within reason, 15:1 ish, and run it on Q16. Going from say 13.5-14:1 and running something like C12, vs 15:1 and Q16, is about 35- 40hp on an engine like that. And as mentioned above, the 598 will make that easier to achieve.

Just food for thought on the c/h comment above. A 1.120 compression height can be used in a 565, 598 and a 632, the same set of pistons can be used in all 3 by juggling deck height and rod length. 9.8/6.385, 10.2/6.8, 10.2/6.7, will allow the same piston to be used in all 3. Keep that in mind when choosing pistons. You may find one that says its for a 565, meant for a 9.8 deck and 6.385 rod, and your building a 598, so you would say, can't use that, but you could, by putting it in a 10.2 deck with a 6.800 inch rod. It just opens up the choices, and a lot of guys don't realize that. Most pistons aren't listed that way.

One more thing, if your buying a new block, get one with .904 lifter bores and a 55mm cam tunnel. Keep in mind, it should clear 4.5 inch stroke. With the 4.75, you would need to run Callies Ultra Hd rods, or clearance the rods to clear the cam. Or a raised cam location. It can open a can of worms though, doing the 55mm in the standard location depending on stroke. The 4.5 works with no issues, keep that in mind.

[peachesracing]

I really appreciate the input guys. When does the .904 lifters and 55 mm cam become a necessity? I have a set of morel bushing lifters that aren't that old but are .842. I have tossed around different fuels and I'm wondering about alcohol? I've never used it before but alot of the racers around here use it. I forgot it mention that this will be used in a mud racing truck. about 3200 lbs, race on a 200ft track

[pdq67]

Imho, a 588"

Low deck block.

pdq67

[BILL-C]

What kind of car and what class of racing are you running?

[peachesracing]

What kind of car and what class of racing are you running?

Its a mud racing truck. 3200 lbs 200ft pit racing

[BILL-C]

The mud truck racing i have seen, the guys run a ton of gear and very high rpm. You too?

[peachesracing]

The mud truck racing i have seen, the guys run a ton of gear and very high rpm. You too?

with my right now I'm running a 5.43 rear gear and using 1st and second of a th400. turning 7500-8000. But that is where my 498 was supposed to make peak power

[Frankshaft]

If it's a 200 ft mud drag, rpm and gear win. 565 all the way.

[rebelrouser]

I have built several engines for mud trucks, very popular around here. 565 big block is a common reliable combination, team I built one for makes 895 natural and they have a 300 shot of nitrous on it. Engine has held up for 4 seasons, even been on its top several times. Trend here is to go to really big inch engines, 600 is average. A guy I work with just got a used 800 inch promod engine for his Jeep. Also the trend is to reduce gear ratio and increase wheel speed.