rrrdad

We are in the process of putting together a parts list for a 496 that will be in our dragster. I will have to use stock heads for the first couple years. I need advice on pistons, cams, lift and expected HP of this engine. Thx M

blowninjected540

Depending on what stock head are you using ? oval ports, square port, 990's, ported or not ?

Do you want to run race gas or alcohol ?

rrrdad

I have both syles of heads available. We will be using Alcohol. To make it simple, just tell me what you would recommend, since I haven't started building it yet the sky is the limit....thx MM

Tod74

IF THE SKY IS THE LIMIT BUY SOME GOOD HEADS. By the time you fix up old stock heads you will be half way to a good set.


14-15 TO 1 COMPRESSION, SOLID ROLLER AROUND .750 LIFT WITH dur @.050 270-280 range 112-114 LSA VICTOR 454-R

JMO although I would probably ask an engine builder. Use the rectangular port heads.

maxpower671

X2! unless you have something useful to add, this is a very good starting place..

rrrdad

ok great thank you. Right now I have to keep the stock heads due to funds. I will get a list of parts With the stock heads about how much HP can I expect? Thx MM

blowninjected540

Skys the limil just have to use stock heads !!!

Start with a good block, Go with a good billet crank, a set of aluminum GRP rods with the best bolt they offer, set of diamond or JE Blower pistons gas ported and buttons with about 13 to 1 compression, a good blower cam from comp cams around a .750 lift with a 7-4 swap, top all of it with a 871 supercharger with around 10 lbs of boost with enderlie bird catcher on alcohol approx 1200 HP. 8) 8) How you doing ???

bixblk

I am comfortable saying that Tod's combo in the above post, with a good set of heads will make around 800HP. maybe even a little more. That should work for you
JMO

rrrdad

ok thanks this is good info.. The two sets of heads I have are 781 and 049 oval ports. What do you think of these? My rods are Eagle H beams 6.385. I will get a Lunati 4340 4.25 crank soon. With the stock heads what advice and what HP can i see with these? Is there any issues with too much crank case pressure when running high compressions? Thx

markdunlap

049/781 oval port cast heads are the best stock heads. However, even mnoidified, they will hold back a 496 engine above 5500 RPM.

To do them right you need to add 2.250"/1.880" valves, unshroud the bowls, port match, have bronze guide liners installed, mill the decks, add good rocker studs and guide plates. Then figure in good valve springs, titanium retainers and 10 degree locks. But they will still be less than 290 CC intake ports. Too small.

A set of RHS/Pro Topline 320 aluminum bare heads can be bought on RJ if you look for $1000. They will take the same parts but the machine work will be done already. They will make 75-100 more HP. And they will have resale value.

If you have to use stock heads, sell your 2 sets and buy a set someone else already spent their hard earned money on doing all of the above, for about $500.