dart iron eagles

[eventhorizon66]

Picking cylinder heads is alot like deciding on the amount of overlap you want.  Too little is alway better than too much, even in a race application.  If you go with too large a head you are reducing port velocity to the point where fuel droplets fall out of the stream and the mixture quality becomes too poor to make good power.  Also consider the fact that airflow gains are seen at increasingly higher lift points the higher you move up in port size.  In other words, not only will velocity suffer, but you may not benefit at all from the added flow because it occurs at a point higher than the cam lift.

My suggestion is this.  If these heads have basically fallen into your lap and you are on a tight budget, try to make them work by running as much compression as possible (which you would do under any circumstance since it is limited to 10:1) and using a milder cam.  But if I were building a combination from scratch, I would use 180cc heads from RHS, Dart, or EQ since that size will support 450-475 hp in a 350 while maintaining port velocity.  Your major limiting factors will be the compression, the dual plane intake, and lift available from a flat tappet cam.

[malibu795]

i agree they are on the "big" side..
or get them take the money you save and do this.

get a 3.75 crank and pistons
external balance 170.00 http://www.summitracing.com/parts/ESP-103503750/
internnal balance 270.00 http://www.summitracing.com/parts/ESP-10350375057I/
KB 135 18cc dish pistons pending on how far you block is deck  you will be ~9.7-10:1
http://www.summitracing.com/parts/UEM-KB135-030/ for 275.00

[eventhorizon66]

A 383 sounds great, but it sounds like he is building the engine for a class that would most likely restrict displacement.

If not, I agree whole heartedly.  Go for the 383.  The 200cc heads will be perfect in that senario.

[hogwild]

no 383 aloud or believe me it would be stroked

[malibu795]

what are the rules you got to work with?

IMO rules state what you cant do as HP requirments... not what you can do.


IMO 7500-8000rpm isnt that high for a 355.

[hogwild]

bought the iron eagles today couldn't resist,rules are no strokers ,10.5-1 max compresion,no roller cams,550 max lift,dual plane intake can be alum,quad carb,headers. i think these heads are going to work the little bit of lost power on bottom end may not be a bad thing on a truck with limited traction,also i dont think it will see under 3000 much.let the engine building begin for next years motor,so far i have 60 over 350 with flat tops and a set of iron eagle heads 64 cc chamber what will comp be?. i welcome any input on this build ,keep in mind truck is not light even though it has been completely gutted

[eventhorizon66]

If you have the block zero decked and use a FelPro Z1003 (.041" thick x 4.166" bore) head gasket and the flat tops have 7cc reliefs (that's assuming alot) you will have 10.21:1 with a true 64cc chamber.  If you deck the head to 62cc you will have 10.45:1.  Do have the block zero decked.  Getting the quench distance in the .035"-.045" range will improve combustion efficiency and net you a bit more power.  Some have gone tighter than .035", but you're on your own if you do that.  At 7000 rpm you may get some piston to head contact.

[hogwild]

pistons have 2reliefs in each one, not four like some i have seen.block has been decked,