Haley'sComet

God I hope so! I have twin Gen V's and I'm stuck in the same "boat" you are...

I love the boat I'm re-working but, there is a limit to how much $$$$ to pour into it verses selling and moving up the ladder.

So far, I'm into my boat close to $8K, with another estimated $7 to $10K to go to get it finished how I want it...

When I bought the 496 (Aluminum) manifolds for my set-up, I was told that they would be a bolt-on to my 454 Mag heads (The rectagular port heads).

I'm not sure about any other application. I was also told that while these manifolds aren't considered to be a "performance" manifold, they would be tons better than the cast set-up I did have.

mcollinstn

The small exhaust valves aren't your friends. You don't NEED the SuperAlloys (great material, but overkill for you), so figure out if you have a buyer for those nice (but small) valves and install 1.90's in a good stainless - or sell/swap the heads for some heads with bigger valves.

A regrind isn't a bad idea with roller lifters, but there are lots of decent available profiles and some low hour sticks available. Lightly used roller cams are an option.

Don't forget to bore-notch your cylinders. Your smallbore block partially shrouds the valves (especially if you are running the right sized ones). There are 25 horses hiding in that one spot.

Best of luck

Budman II

iTrader: (1)

Thanks for the reply, MCCOLLINS. Would the Ferrea 5000 series or 6000 series exhaust valves do the trick? Would you stick with the oval port 781's with the bigger valves, or go rectangle port? I can pick up a set of used rect port heads that already have the big valves for around $300. Would that kill the low-mid range power too much?

I have not heard of a 1.9 BBC exhaust valve. Would 1.88 work as well?

pantera232

All of the 781 heads i find are the stock small valves..

Bore notch you mean cylinder heads??

IM doing a similar build now, bore out cylinders, new pistons probly cast, rm cam, sm exhaust, edlebrock intake,
found a set of 781 one heads but they have stock valves, im going to upgrade springs and valve components..

I wanted to find the bigger valves but cant ppl say it wont be much diff, and bigger valves barely fit in that small 110 cc head

Budman II

iTrader: (1)

Pantera, you are correct - 781 ovals (like all GM ovals) came with 2.09 / 1.72 valves. I was referring to whether it would be best to run a set of 781's with the larger valves installed, or just buy a set of square port heads that already have the 2.19 / 1.88.

Bore notching revers to putting a deep bevel at the top of the bores where the intake and exhaust open into the cylinder. Many of the factory high performance 4-bolt blocks had this. It unshrouds the valves when they open into the cylinder and promotes flow.

BTW, those 781 heads should have a 119 cc chamber, not 110 cc. Same chamber as the 088 and 990 square port heads commonly found on marine engines.

picklenjim

$300 is a good price for those heads. I would probably buy them to put on the shelf. If the valve's are good in them you could use them to switch over to the ovals if you wanted to stay with the ovals. Remember buy going to larger valves in the ovals you are also going to need some grinding work done to blend to the larger valve size. Also some unshrouding of the valves in the chambers. If it were a 454 I would deffinately say ovals. With the extra cubes you might be alright with the rectangular ports if you plan to spin it high. Hard decision as to which would actually be best but I'm think'n the ovals. Just re read your opening post and remember now you want a dependable budget build so I think I would deffinately go oval. Prop to keep under 5400rpm's. Here's an interesting link to a flow comparision between ovals and rectangular port heads.
http://www.maliburacing.com/ovalvsrect.htm

Budman II

iTrader: (1)

I thought about that too - the cost of new inconnel exhaust valves would approach the cost for the complete set of heads. He said they have around 250 hours on them, but I need to see them in person to make the call. They look tired in the pictures, but it's hard to tell anything from that. The article you posted definitely helps me to decide on the ovals. I can get the 781's for $100.

There is a guy on the chevelles.net forum (goes by VortechPro) who is apparently making some pretty stout numbers on 454 builds with the 236 casting peanut port heads. He is doing some port work on them, adding 2.19 / 1.88 valves, and going with a mild 226* 236* 112 LSA hyd roller. He is dynoing these things in excess of 550 HP. Apparently, it's all in the combo of parts.

pantera232

The guy that is trying to sell me the 781 right down the street from me with a fresh valve job and very clean but with the small valves wants 900.

Budman II

iTrader: (1)

His bag's loose! You could score a nice set of lightly used Merlin ovals for that price easily. I guess I better buy up all the 781 castings that guy has for $100 / pair!