Porting sbc heads?

[Tom68]

I'm surprised there's no love for the 2.02 valve, since this engine will be 4412 restricted it will have high manifold vac at high valve lift, assuming a 2.02 flows more at low lift than a 1.94 (it bloody better) that's one way of getting some fill from a week port flow situation, I'd have thought.

With high vacuum in the manifold at WOT, which direction do you think that low lift flow will be heading?

To the even lower pressure in the cylinder.

[SoCalDave]

This works in conjunction with maximizing valve job flow ( D x.18, and the 85% rule .

That's a good image to follow. On the cylinder wall side raise the roof and make the bowl wider than the center of cylinder side (next to exhaust valve). Make the throat larger for intake and exhaust, plus make the bowl larger for intake and the exhaust.

[Dave B]

I could of lent you a engine from the 70s same cc area heads and raised floors and raised and moved ex ports with 50 less cubic inch and made same power you are now Chad.Of course a auto trans would be a wasted effort.Its fine if you like dinosaur stuff and tonka trucks and barbie cars and dial pay phones ,have a blast .Allot of the world has moved on and saw real hp out of 358 engines. I see 1050 hp 358 as what today's engines should have, anything less with what's available isn't trying in full race format.If you set national record with 70s tech ,I will run right over to Gaye's Kansas and shake your paw.lol

[SpeierRacingHeads]

I could of lent you a engine from the 70s same cc area heads and raised floors and raised and moved ex ports with 50 less cubic inch and made same power you are now Chad.Of course a auto trans would be a wasted effort.Its fine if you like dinosaur stuff and tonka trucks and barbie cars and dial pay phones ,have a blast .Allot of the world has moved on and saw real hp out of 358 engines. I see 1050 hp 358 as what today's engines should have, anything less with what's available isn't trying in full race format.If you set national record with 70s tech ,I will run right over to Gaye's Kansas and shake your paw.lol

I don't care what you think. Line up next to me or one of my customers in Super Stock you bad ass..

But you hide behind a screen name and talk shit, like a little girly... And it crystal clear you know nothing about Super Stock.

[RDY4WAR]

Guys, let's grind the heads on the engines and not the ones on our shoulders. Cool?

There's a good bit of talk about the throat and bowl area, but not much about the bottom side. In general, how well do OEM cast iron SBC heads (882s for example) respond to laying back the short radius?

[88bluestar]

Can anyone post some pics of bowl work, etc in regards to these heads?

[mag2555]

If one takes a half hour to make 2 templates you can then easily see how close the stock short turn relates to the stock throat size.

[barnym17]

The reason I play with dinosaur tech is I like it.And many many race classes demand it I can put a turbo Ls in a modified but nowhere to race it. Besides Dave You already gave the reason we do it' Because we aren't mail order warriors just because your vette is fast with "all parts from jegs or stock"My grandaughter can order off the internet and shes 7.

[steve cowan]

Can anyone post some pics of bowl work, etc in regards to these heads?

Have you done valve job?
That's first on the list and work from there.
Not sure how much time and money you are putting into these cylinder heads you are required to use.

[88bluestar]

Can anyone post some pics of bowl work, etc in regards to these heads?

Have you done valve job?
That's first on the list and work from there.
Not sure how much time and money you are putting into these cylinder heads you are required to use.

Since my car is a bit on the heavy side with me, added weight ballast to get all the right percentages for racing I figure 1.94/1.50 was the way to go. So whatever is best for the rules I have is the direction I'm going. We have a very well established head builder near where I live that I've taken numerous stuff over the years with great success. How done no work yet but trying to determine what valves are best to accomplish the best valve job, whether it be a 3 or 5 angle job I'm open to spending what is needed to make them the best possible with the rules I have. I may see what his cost would be to do the required porting, especially with my novice level experience lol!

[barnym17]

I understand wanting more power but in my opinion far more important is weight,get that puppy under your minimum and add ballast where you want it will way more speed than the horsepower pickup will.

[Tom68]

added weight ballast to get all the right percentages for racing

Move stuff.

[Walter R. Malik]

Ok, I must preface this question by saying this is a budget class so I’m trying to use what I have but make as much power as I can. Rules are:
Engine must be vacuum-pumped and measure no less than 14 inches of vacuum at 900 rpm. Must have a 3/16-inch port in the intake manifold to hook up vacuum gauge. 4412 Holley gauge legal allowed.

6,200 rev limiting device and must weigh a minimum 3,000 lbs., including driver after race. Must run factory cylinder heads (no aftermarket race heads allowed). Must run flat top or dish pistons. Must have a cranking compression no higher than 150. Must run factory-style stamped steel rocker arms.

What I have is an 350(010) block, 4340 used 3.750 stroke crank(20 main/30 rod main, and 991 open chamber heads.
3/8 mile dirt track. Using pump gas but eventually will be running E-85 fuel.

What porting would I need to do and other mods to make the 991 work as efficiently as possible within these rules?

Anything representable in power will be fine ... work on the car.

[Wetflow]

Anything representable in power will be fine ... work on the car.

X2....especially if there is a claimer rule on the motor. Is there a claimer rule?

[88bluestar]

No claim rule. The car only has so much weight that can be removed, it’s already gutted quite a bit. For this type of car it’s at its ideal percentages to get proper bite and forward traction.