408 head question

so here i am again with my 408 o decked with flat tops wondering if 76cc dart iron eagles milled to 74cc will lower my compression ratio enough to use pump gas?


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Yes, As long as you tune it real well and run a healthy sized cam. 10.4:1-ish.

these are my cam numbers- advertised duration-480 lift, 268intake, 280 exhaust with 110 degree lobe separation- duration at 50 thousands is 224 intake and 230 exhaust. this is also known as the 1179 grind at oregon cam grinding. feel free to make suggestions since a cam swap is easy at this point in the game. thanks again for all the info

My first suggestion is NOT THAT CAM. Way too much exhaust duration. I recomend starting a new thread for a cam recomendation. In it include your engine build specs, your ehad flow numbers if avaiable, intake, exhaust, carb, trans, gear ratio, stall speed (if auto) and intent (race, cruise, etc.). That cam you have now would be good if you put a 175 shot of nitrous on your engine.

Depending on what you are doing you may want to run a larger camshaft. That cam will make a lot of torque in a 400 but I think it will peak around 5,000 rpm or less. You can probably run a little more lift and duration to extend your power without hurting your low end torque.

I'm 99% sure you will get detonation with that cam with proper timing... you could probably tune your way out of it but you will leave power on the table and probably drivability... you need more duration to bleed off cylinder pressure at lower rpms.

Milling the heads will raise, not lower the CR. I would leave them at 76 as long as they are flat.

yes i know that milling raises compression, heads have a fresh rebuild and i was just giving all the info i could about them. can anyone suggest a cam for this setup? what kind of lift and duration am i looking for? should i just call comp cams, im nervous about that because a so called expert suggested the cam i have now. who do i trust for info?

Not Comp. try Isky. Less marketing because their cams speak for themselves.

There are peolple here that can help you. The 400 in my 4x4 truck is cammed differently than the one I built for my Dad's S-10 and that is cammed different than the one I am doing now. What exactly are you trying to do ? What type of vehicle, drivetrain, exhaust, intake etc. ? How do you want the vehicle to behave ? Smooth idle high torque limited rpm or something a little more exciting ? I think you are looking for something a little nasty since you do have Dart Iron Eagle heads but are they 180cc or 230 cc or somewhere in between ? Sure get some ideas here and talk to a cam company too.

i have a 1979 caprice aerocoupe with 3:42 posi, 2 1/2" dual exhaust with long tube headers, air gap intake, dart iron eagle 76cc milled to 74 with 1.94's and 170 runners. i know the heads are a little small but they were 300$ fresh from the shop. dart said they would be better than any stock head i could get so i went with them for now. as for carb i am in limbo because i have a mighty demon 650 e-85 carb thats brand new but i am nervous about using it because i have no experience with e-85, so i was just going to break her in with my 1406 edelbrock then try to figure it out. what do you guys think about breaking in an engine with e-85? as for what im looking for, a car that 20 pounds of vacuume at idle and around 1000 hp LOL, no really its going to be an everyday driver for around town but i want it to be nasty of course, mabye a couple of passes a year at the track.

Are you going to run E-85 after breakin ? What transmission and torque conveter do you have ? I don't think those are Dart Iron Eagles I think they are the stock relacement head. I can't remember what they are called.

not sure with the e-85 yet. i have been wondering if it might be a good idea to keep around for summer when e-85 is actually cheaper than gas. right now 1 mile from my house is e-85 for 2.01 a gal. the heads are drt007 castings and the specs are dart iron eagle s/s heads with 165 runners and the 1.94's

You are right on the Dart Iron Eagle S/S. That cam you listed will make a lot of low end torque and be very civil in a 400. Personally I would use something with a little more lift and duration say 230/236 @ .050 or thereabouts ans stay at a 110 lsa or a little tighter for a choppier idle.

165cc runners and 10.4:1 compression on a 408 do NOT mix well. You need to get those heads seriously ported out, or swap in a different piston to get something around 9:1.

Those heads are small even for a 305 when you're running that much compression. No cam can fix that. you can still make it run, but it will be leaving a LOT on the table. I say do it right the first time.