Bolt-on hp- C8/C9/D0VE vs D3VE on '75 460

I am having a very difficult time finding a set of C8/C9/D0VE heads locally. I found a set a D3VE heads still on motor at the local Tear-a-part salvage yard. I know these are what I already have, but need to keep the truck running while I build/port heads to swap on. If all I do is clean and port the heads, with an Edelbrock Performer intake and 650 cfm carb, what kind of hp difference am I looking at between the D0VE vs D3VE heads? I'm on a tight budget, so I need info to help decide if the extra $100+ will be worth having it to have C8/C9/D0VE heads shipped to me.

Never mind.

Both sets of heads D3 and D0 will support the same level of hp when properly set up. The early style C8-D0 heads are "bolt on" power because they have smaller combustion chambers that will raise your compression ratio. This swap will more than likely need to have a set of roller rockers and guide plates added to the cost, because the two styles use different types of rockers.

schmitty wrote:Both sets of heads D3 and D0 will support the same level of hp when properly set up. The early style C8-D0 heads are "bolt on" power because they have smaller combustion chambers that will raise your compression ratio. This swap will more than likely need to have a set of roller rockers and guide plates added to the cost, because the two styles use different types of rockers.

X2 on what Dig Daddy said

I did know that they'll handle roughly the same hp, but I'm not planning on pulling the engine and doing a full rebuild or replacing the entire valvatrain and running high RPM's. I'm not PLANNING alot of pulling with the truck, but I'm want to keep the RPM's around 5,500. I mainly wanna bring the engine's output back up to the pre-emissions level, but keep it pulling hard in the low RPM range. I'm on a tight budget and would like to keep the stock valvetrain, if possible. Like I mentioned, I'm inquiring about the diff in bolt-on hp between a ported C8/C9/D0 and ported D3, not potential hp handling. I can't find a local source for a C8/C9/D0 and would need to ship in a set, but can pull D3's at the local salvage. Trying to decide if paying the extra $ will be worth it for the extra CR and hp gain. Thanks for your posts.

Stock dish pistons and a set of D3 will barely break 8:1 compression, so yes IMHO it would be worth the $100. 00 for the Dove's. Unless you are doing some heavy low rpm pulling, and need the lower compression. You will be close to 9:1 with the Dove's perfect for a street engine.

I'll second what Blake said.

Travis

My 460 bored .030 over with D0VE's, chamber cleanup bigger valves and -25cc dish pistons will be just about 9:1 compression. That way I don't have to worry about detonation with pump gas. I mean, your going to drive it on the street so you want that lower compression so you can fill the tank with unleaded. The D0VE's will raise the compression and the power whilst still keeping compression in a safe range. IMHO

No on the heavy pulling. At most, I'll be hauling the occasional firewood load or full bed load, but not much towing. Just looking to open up the motor close to pre-emissions output and keep it a low revver. If I want a car to rev like crazy, I'll get a Honda. Lol

Put in an early timing chain set while you are at it, it's gonna wake that engine up quite a bit. Remember to add about $400 in the budget for the rockers studs and guide plates if you decide to do the switch.

Thanks for the posts. The D3's I can pull locally run $52-70+tax per pair where as the best price on the C8/C9/D0's is $190+s/h. So I'd be looking more like a $200 diff + mods to make the C8/C9/D0's fit.

Oh, and to verify, what all valvetrain parts are needed for the C8/C9/D0VE's? Prior to this post, I was told that I'd just need to change the rockers and MAYBE the pushrods.

You will need guideplates and studs. The pushrods are up to you, but a decent set of 3/8" pushrods aren't that much money.

IDT-572 wrote:Stock dish pistons and a set of D3 will barely break 8:1 compression, so yes IMHO it would be worth the $100. 00 for the Dove's. Unless you are doing some heavy low rpm pulling, and need the lower compression. You will be close to 9:1 with the Dove's perfect for a street engine.

I don't want to hijack, but that is what I am using in my F100 now. D3's and dished 2404 pistons. It tows great on 87 octane, even in the mountains. How do y'all think 9:1 would tow on 87? (open car trailer about 5000 lbs with my Mustang on it) I realize the cam and gearing will affect it, but anybody try this? This should help the OP too.