jrg77

I wish I had known this before I ordered the Eagle kit I did. I could have gotten away with a smaller dished piston (30cc!). As it stands with 64cc heads I am supoosed to be about 9:1. How much difference is there in 1 point of compression? Is it based on a percentage or just a rough number?

DevilsAddvocate

If you are not racing in a certain displacement class it is RETARDED to take cubes away. What the hells the point the more cubes will always make more power as long as it has the air/fuel demand that it needs. Have fun on ur build tho since it must be kool to destroke it , whats the point of the 6" rods instead of the 5.7" rods or even stock 400 length. Itll rev even faster and higher and thats kool

WhiteLightnin83

hey buddy no need to be a dick about this, obviously you've never driven a 377 destroked motor.... it doesn't take away power, if you weren't so niave and pesimistic you may understand this, but hey... someone's gotta be the ***** on the forum right? he's running a 377 that ran an 12.37 at 131 but i guess that's probley not as fast as that sbc ur building is it? all this with a bill that doesn't even clear $7000.... but whatever, all i did was make a suggestion...

DevilsAddvocate

As a matter of fact no its not as fast as the sbc i am building but thats another story ill post a vid when shes done. Im not trying to be a dick but why are you trying to give him bad advice. What is the advantage of making your motor smaller? Why not throw a honda motor into your camaro those can rev to the moon. That doesnt equate to performance tho. Tell me what advantages he has to making his motor smaller im really not trying to be a dick just trying to see where you are getting at.

Z28SORR

Don't want to burst your bubble, but more ci. is ALWAYS better than less, in the same package.
Racing orgaizations don't restrict the ci. of the different class engines because smaller ones make more power.
Chevrolet didn't go from 5.7L to 6L in the Corvette, because the 5.7 made more power.
Pro's don't build 5000hp elephant engines because they can get it from a small block.
Think about it.

82355

Wrong, a 302 Chevy will run much better than an equally prepared 305.

Martin

jrg77

Can we get back to the which heads are ideal for my car?

The 408 is cast in stone (or at least hypereutectuc steel).

Jason

DevilsAddvocate

lol smart ***, bigger displacement of equal bore size. General Rule of thumb

Big Bore, Small Stroke is Better Than Small Bore, Big Stroke of equal (or almost equal likes lets say 3ci's ) displacement.

However Big Bore, Big Stroke is better than both.

LilJayV10

Depending on your cam selection, which actually should be based from cylinder head flow numbers anyway, I think you would want a 200-220cc intake runner with a 2.05/1.60 head. The way it was explained to me from my machine shop, and I trust these guys, they won the NMRA nostalgia class last year, that a 2.08 intake valve on a street car is a little hard on the spark plugs because it dumps so much fuel into the chamber at low rpms, on a full race engine it isn't going to matter. Mike said they have found the 2.05 to be a good compromise. and unless you are turning some really high rpms, he said a 2.08 wouldn't be really benefical either.

The first thing to consider about your heads is your budget. How much are you willing to spend? Remember, heads it what makes power, before anyone jumps on me, yes the right cam and intake and so on is important, but if you don't have a cylinder head with good technology, flow characteristics(sp?)(I didn't just say flow numbers) then you aren't going to make really good power.

you have many options, AFR, Motown, Dart, edelbrock and so on. Dart has a new line of platinum heads that are supposed to outflow their iron eagle heads by 15%+. These are supposed to be better than the protopline heads that I have, and the platinum heads are very reasonably priced. Again, it depends on what you want to do with the engine. Pick an aproximate RPM range, which I think you have, and find a head that will flow enough air, then from the flow numbers pick a cam, or call a manufacturer and discuss what you have and wanting to do and have them pick a cam for you.

As far as big engine small engine, yes, a bigger engine will make more power if it's components are larger also. What I'm saying is you see a lot of people build 383's, and put cam/heads on them that are ment for a 350!! Then you have a ****ty running 383. Look around on this board, there are several out there. You HAVE to go with a bigger cam and heads to take advantage of the cubic inches. Thats why the build up we did for the 93Z was a 350 and not a 383, he already had the heads and cam, and putting it on a 383 would have been a waste of time and money. Just my .02

Jason

jrg77

I'm will to go $1400. At a $1000 I'm at the Edlebrocks, but from what I've read AFRs can be had from as little as $200 more to about $400 more. Brodix are in the same range, just as Trickflow. The challenge is that they obviously work for different applications, and I can't figure out which ones are best for mine.

If the difference is only 20hp then screw it I'll just get the Performer RPMs and make my local guy happy. But If I can get 40-50 more then it might be worth the jump.

I've been told by numerous people on numerous boards that you cannot pick the cam first. It still makes sense to me - pick a cam with the right range, find heads that flow in that range, Voila! But folks get upset with me so I'm playin along.

I'm even willing to throw up the $900 its gonna cost to go hydraulic roller is it will really make a difference. My local guy says it won't.

Jason

LilJayV10

The thing you have to watch out for AFR is all the little crap they tack on, like bigger springs, bigger studs and so on. I agree, you really can't pick the cam first, you can get an idea put picking the cam goes hand in hand with picking the heads.

You can get lucky and score a set of used heads, have them checked first, but thats always an option.

I went with a hydraulic roller setup in mine, I got is from a board member on the thirdgen.org board for a good price.

I don't have any personal experience with edelbrock heads, some people have good luck others not so much, but there's always more to it than just one part of the combo.

You are going to want a head that flows 270cfm+ range, maybe more with respect to low lift numbers and velocity.

92RS305#2

wow. that is an ignorant statement. in general i guess you could say that bore is oriented towards hp while stroke is more oriented towards torque. so with that stated you stroke an engine and you gain torque, but to a point your pistons have farther to move and there's more weight on the rotating assembly and in the end you limiting your max rpm. in certain situation i can see the reason for destroking an engine as it can make you rev faster and higher, this gives an advantage when turbo charging as you make more power at higher rpms. if i was looking to twin turbo a 454 block i'd definitely put in a 400 crank to allow me to rev higher and faster, but if i wanted a supercharger i'd prolly put in a 500 or so crank so i can have the push to get the supercharger pumpin. n/a i'd prolly keep it at a 454. in saying that more CI is always better is one of the stupidest things i've ever heard, even if its the same bore. don't make yourself look ignorant please.

WhiteLightnin83

thank you 93rs, finally someone not so pesimistic and niave.... if making your motor smaller is such a disadvantage then you need to reconsider what your idea of disadvantage is.... a longer stroked motor has a shorter power band if you could say so. from 1500 to 6000 tops on a 383 whereas the 377 allows the same amount of power but over a much more broad range, in my friend's case its from 1500 to 8000 rpms and i guess if you consider that less beneficial then thats ur opinion. but more CI does NOT always mean its better. match this 377 to any 400 around with a near equal price tag on it and the 400 would be goin home with silver.... the entire reason i even posted wasn't to say that the 400 was worse than the 377 all around, but this guy seems to be concerned with his rpm range to turn the 400 so it sounds like a 377 would do him well since rpms are the main benefit of this motor....

jrg77

[QUOTE= the entire reason i even posted wasn't to say that the 400 was worse than the 377 all around, but this guy seems to be concerned with his rpm range to turn the 400 so it sounds like a 377 would do him well since rpms are the main benefit of this motor....[/QUOTE]

You are right that is my focus, but I already bought the rotating assembly, and it will be at least 400 (I think 408 at .040" over).

Jason

92RS305#2

sorry to hijack, its sounds like you've done your research and know alot about what you want. good luck with that