[79Poncho]

Hello all,

I'm in the planning phase of my 455 build and I'd like to see what people's thoughts are on the value of porting work for my build.

I've got a '74 4-bolt main 455, std bore.

I'm planning to run forged pistons (Sealed Power L-2359NF - Speed-Pro Forged Pistons) with stock rods on a stock crank

I'm considering the SD performance hydraulic roller "Stump Puller" grind

I have a set of 6x-8 heads that came off a 400 that I wiped the crank on. They've been milled to reach 93cc chambers and have 2.11 and 1.77 valves. I think it's about 9.57:1 compression.

I've thought about porting these heads at home using Jim Hand's book, but am hesitating to get started due to repeatability concerns from port to port. I'm considering if it's worth to do the work myself, pay to ship the heads to SD Performance for CNC work, or just bolt them on as-is and see how it runs.

I'm not looking for anything crazy, any form of 455 is a bump up from the Oldsmobile 350 small block I'm running now.

Thoughts? I'd really like to hear from guys building and running mild 455 combos to see what the impact of 20-40 cfm really is.

Thanks,
Geoff

[steve25]

A lot!
The long stroke and piston speed of a 455 makes them starved for air very fast!

With stock iron D port heads they hit peak hp by 4200 rpm, even with high lift version of Cams like a 068 clone!

[ponchjoe]

I built essentially what you are planning with the exception of the roller cam ( I used the Voodoo 704 HFT). I put a set of ported to Jim Hands book casting 96 d ports on it and it was very healthy and streetable. I would pay someone to do it as opposed to doing myself for the exact reason you cited.

[455rebel]

I would think, that on a low red line rpm mild 455, 5200rpm, that port matching would be enough! That's all I did when I put the 400 heads on. With a cliff spec qjet, blowing through stock logs, it's still pulling hard at 5200rpm! Never turned it any more than that.

[steve25]

Stock 6X heads a 455 with a Cam of some 230 Intake duration at .050" with about a .480" lift will net you some 380 hp without much trouble if your compression is atleast 9.2 to 9.5 if that's all your looking for under your right foot.

[389]

I would use forged rods, clean the heads up but not port them and run a nice 068 cam. Keep it stockish.

My buddy used to pull them right out of the junk yard in the seventies and turn 11s with them in his Nova/Ventura. He was always on the look out for a smashed up 70 Grand Prix, Grand Ville, Bonneville because they were still high compression but he later found out he turned the same times with the 71-72 motors...

I would also look into these Voo Doo cams that have out now. People seem to be having good luck with them...

[ta man]

It really comes down to how much you want to spend and honestly how much horsepower you want.
Your stock 93cc heads will work very well on a budget 455 build with the right chosen cam . Most likely be in the 375 to 400hp range with gobs of torque.
Home porting the heads if done properly, opening up the pushrod holes to run 1.65 rockers choosing another cam will get you in the 400hp to 450hp range.
Now if you want to run SD's roller cam..you need your heads set up for the higher lift that that cam provides..as well as additional porting..you may as well send the heads to SD or buy a set . This setup would be in the 500hp plus range but at a cost.
Option 1 cam lifters $200 to $300..
Option 2 cam lifters $200 to $300 valvesprings $200 to $300 rockers $200 to $400..time and porting tools?
Option 3 cam and lifters, pushrods,dist gear $1000 to $1200, heads $1200 to $2000
I've personally done all these builds in phases other than Option 3 I wound up at option #5 which leads to option #10

[ANDYA]

You have to ask yourself what kind of performance your after. A 455 with stock heads and 068 type cam will give you 370-400 hp. Some good porting and a performance cam can get you 450+ hp. Either way I think a stock 068 cam in a stick shift 455 is too small. The one upgrade I would make which ever way you chose is to go with forged rods. It just doesn't pay to use stock rods. By the time you clean, debur, polish, resize , install new bolts and balance stock rods you end up with something that's weaker than an inexpensive forged rod.

[ta man]

It really comes down to how much you want to spend and honestly how much horsepower you want.
Your stock 93cc heads will work very well on a budget 455 build with the right chosen cam . Most likely be in the 375 to 400hp range with gobs of torque.
Home porting the heads if done properly, opening up the pushrod holes to run 1.65 rockers choosing another cam will get you in the 400hp to 450hp range.
Now if you want to run SD's roller cam..you need your heads set up for the higher lift that that cam provides..as well as additional porting..you may as well send the heads to SD or buy a set . This setup would be in the 500hp plus range but at a cost.
Option 1 cam lifters $200 to $300..
Option 2 cam lifters $200 to $300 valvesprings $200 to $300 rockers $200 to $400..time and porting tools?
Option 3 cam and lifters, pushrods,dist gear $1000 to $1200, heads $1200 to $2000
Option 1 is a great street engine..and is actually a good choice.and the rest can always be done in stages , I've done it that way over the years and its quite rewarding. I personally skipped option #3 and went option #5 .

[Stripes]

Looks like the real question is mild or wild? In our 455 bored 60 we added a very mild hyd roller and out of the box d port Edelbrock heads. The E heads got us hardened valve seats for todays gas, better flow, less weight and good compression along with new valves and springs set up for the cam. With the stock iron intake, and we made 500 hp, 577 tq on the dyno. Compared to the same engine with iron heads and a mild hyd cam, the difference was immense. This car still idles at 750rpm and has 16 lbs vacuum for the power brakes. But cam selection is very tricky, so consider a minimum of 236/242@50 and a 114ls to calm the idle.

[android 211]

If you don't know what you are doing with the die grinder you can spend a lot of time without doing much good. The trick is to not try to recontour the port but to improve certain areas. Streamline or tear drop all the valve guides. Knock back the pushrod hole bulge inside the intake port a little bit. Polish the exhaust port but not the intake port. Smooth the bowl area on both intakes and exhaust ports. If the exhaust seat was opened up for the 1.77" valve then make sure the bowl area was smoothed to take advantage of the bigger valve. This will take a couple days to do. Thats why it costs so much. Its worth 50hp supposedly.

[Brian Baker]

A bowl blend into the seat and a gasket match doesn't require much skill to repeat the results from port to port, and the power gains will be worth it. You don't have to remove that much material for a respectable gain in flow.

For what forged rods cost these days I wouldn't even bother with stock cast rods. The money you spend reconditioning them and installing ARP bolts will be better spent on the forged rods.

Here's a link to some old school combo's that would still be respectable today, and pump gas friendly.

http://pontiacstreetperformance.com/...turedcars.html

[tom s]

Stock head 455 SP II cam build
http://forums.maxperformanceinc.com/...d.php?t=804201

[455rebel]

I still vote for a port match, and mild bowl blend, and i like to remove all the cast iron flash.

[ta man]

Originally Posted by Brian Baker

A bowl blend into the seat and a gasket match doesn't require much skill to repeat the results from port to port, and the power gains will be worth it. You don't have to remove that much material for a respectable gain in flow.

For what forged rods cost these days I wouldn't even bother with stock cast rods. The money you spend reconditioning them and installing ARP bolts will be better spent on the forged rods.

Here's a link to some old school combo's that would still be respectable today, and pump gas friendly.

http://pontiacstreetperformance.com/...turedcars.html

There is some really "Handy" information on that site..and the forum is still active. I always wanted to be in the 1 to 1 club.

[77 TRASHCAN]

Originally Posted by ta man

There is some really "Handy" information on that site..and the forum is still active. I always wanted to be in the 1 to 1 club.

Ernie, I believe you are in the 1.5:1 club, Lol

[ta man]

Originally Posted by 77 TRASHCAN

Ernie, I believe you are in the 1.5:1 club, Lol

Not quite! Maybe someday..more like the 1.25:1 club

[Brian Baker]

I was a moderator/judge for the 1:1 club when the site was "super active".

[beertracker]

If you are going to port the heads yourself take very small cuts. Only enough to smooth the casting. You will need to air flow bench so you know how much better the heads flow.

If you have a engine dyno program you can factor in ported vs non-ported heads and see the power\torque differences.

[lust4speed]

I would recommend sending the heads out. There's nothing better than lots of experience for good porting. That translates into the 20th set of heads you do will be great - and by then you will realize just how badly you butchered your first set of heads.

If you do want to learn, the best advise I can give is to do small steps and complete each step for each port. Start with gasket matching all eight intake ports and nothing else, then lightly clean up all eight pushrod bulges, and so on for both heads. Spending a full day on the first intake port will really screw you up on day two when you try and remember all of what you did on day one. Plus if you throw in the towel after a few days the ports will be pretty much equal and the heads can be run with the minor improvements. If you stop with three out of eight ports done you're screwed.