[77 TRASHCAN]

Hey Steve,
I keep thinking of this thread. You might be asking a question about doing something that's seldom been done...
The ideas presented sound good.

Jim Hand says the port volume of most 68-up "D" intake ports is close to the same. I'm guessing a set of 6X-8's might be the ticket for this potential build?, knocking off the sharp edges in the ports, keeping the port volume as small as possible for port velocity, comp. ratio of a little over 9:1. zero decking the block for utmost combustion effeciency.

I used a Sealed Power CS641 (duration @ .050 198 degrees, intake, 208 degrees exh, LSA 111 degrees) cam in the 350 that currently resides in my 77 T/A. Sealed Power lists it as a replacement for the 066 and 067. It gets fair MPG, but I've never spent enough time on it to try improvements. I bought a SP2P to try on the 350, and have a regular performer I plan to try also

My T/A got excellent MPG when stock (stock as in COMPLETELY stock, I removed the cat converter,only). 21 MPG was not uncommon, Got 22 MPG several times. All this WITH the EGR functioning...I like the idea of using a larger torque engine (couldn't think of a much better one than a Pontiac!!!), and lugging it out on the highway getting the RPMS low enough to hopefully get some decent MPG #'s...
THe stock cam in my T/A was a teenie weenie cam (which developed a flat cam lobe @ around 60-70,000 miles) Sealed Power has a replacement cam for the small cam, also, it's a CS690, .364" gross lift. My car ran very well with this cam, I think it's the same cam (spec wise) you have in the 265.

I sold 3 Comp Cams 260H cams, (these are NOT the XE cams) in the good old days when I sold auto parts. The cams I sold went in 77-78 T/A 400's. Everyone liked how their cars ran after the switch. I wonder... about that cam for a 455

I'm curious what others say, especially concerning cam selection, comp ratio. With the ability to tune a Q-Jet so finely (thanks to Cliff!!!) I think some good results are around the corner.

I want to try a MPG oriented 400 in my T/A. MY car currently has the 2.41 gear in ti w/ the 350 engine. I have a TH350 lockup from a 81 turbo T/A, it would knock the RPM's down another 300-350, putting in in the range of your setup. I'm loosening my strangle hold of not caring for O.D. tranmissions after reading Cliff's book on them...(may never own one, but...)

I wonder about the use of stock exh manifolds. A 455 has a pretty fair amount of air flowing through it. Don't want to choke it, but the volumetric effeciency is at a low RPM, stock exh manifolds might be the ticket...

Steve, I pray for a great 2012 for you, lookng forward to seeing this build!!!
Jeff

[U47]

The problem with 6X heads is chamber volume and MOST importantly large valves. What is needed is a 1.96 / 1.66 and even better is the 1.88 / 1.60. The problem with 1.88 / 160 is the bathtub/valve shrouding chamber design, so the 1.96 /1.66 open chamber head is the best bet.
Large valves are fine in a performance application, but if you are going for mileage you need port velocity at low engine speed and the small valve small port diameter does the job better. That is also why I recommended the performer small port intake manifold. That is also the reason Cadillac engineers designed the 472" and 500" engine with small valves to be able to keep the torque and have decent mileage for a 5,000lb. + car.

D.

[password taken]

I've got a sp2p I'd let go cheap. Just pm me

[Steve Barcak]

This 455 engine project for my '61 Safari is definately evolving. Last week it was going to be a 6X 068 1.5 rocker deal. Now am leaning toward a set of small valve heads and trying a tiny cam like the 066 or even the '59-'63 2bbl cam.
Of course, these things can all be changed if I am not happy with it.
On the early heads being closed chamber- true. However, I can modify them to an open chamber design and get a more attractive chamber size too for my displacement. I opened and cc'd chambers on 670 heads in the mid 80s and also opened the Super Chiefs on my Fueler.
A few days back , I brought in a pair of #15s. They tore them down and one head had a 30 intake seat, the other had a 45 seat! uh.
Now going to look around my yard tomorrow for a pair of small valve heads. Will pull them off and get them into the machine shop. I'd prefer not to have to buy a new set of valves for the little buggers. We'll see.

Also would like to try a sp2p as well.

This wagon will use a 2.56 rear gear with a 700r4 and headers. It is the same combo I have my GTO and I really like it. I do not use the lock up. Engine runs between 1,200 and 1,800 rpm most of the time and has decent vacumn. 455, 6X heads, 068, 1.5 rockers, 3 tube headers.
I use headers on almost everything. I like them.

[U47]

[QUOTE=Steve Barcak;4507477]This 455 engine project for my '61 Safari is definately evolving. Last week it was going to be a 6X 068 1.5 rocker deal. Now am leaning toward a set of small valve heads and trying a tiny cam like the 066 or even the '59-'63 2bbl cam.
Of course, these things can all be changed if I am not happy with it.
On the early heads being closed chamber- true. However, I can modify them to an open chamber design and get a more attractive chamber size too for my displacement. I opened and cc'd chambers on 670 heads in the mid 80s and also opened the Super Chiefs on my Fueler.
A few days back , I brought in a pair of #15s. They tore them down and one head had a 30 intake seat, the other had a 45 seat! uh.
Now going to look around my yard tomorrow for a pair of small valve heads. Will pull them off and get them into the machine shop. I'd prefer not to have to buy a new set of valves for the little buggers. We'll see.

Also would like to try a sp2p as well.
__________________________________________________ ___________________

Steve, the #529472 (D) cam which is the 59's 2bbl. 10.0 comp.280HP automatic, 60-64 283 hp 10.5 comp.automatic is exactly the same grind as the 97779066 (N). I would still suggest the smaller (U) cam and it works with high velocity small valve heads. I had a set of 15's on my 455 for a while, but I needed 5gals. of aviation fuel to 15gals of 92 premium to keep the 10.0 compression from detonating although you could use dished pistons.
D.

[Jack Gifford]

Steve- why not use the lockup? I like having the lockup in the Suburban (only functions in 3rd & 4th of the 700R4).

Years ago I put a Fairbanks low-stall converter in a slightly-modified 289 Ranchero and saw about a one-MPG improvement in the long term. Anybody offer a low-stall lockup converter?

[Steve Barcak]

Originally Posted by pontiac jack

Steve- why not use the lockup? I like having the lockup in the Suburban (only functions in 3rd & 4th of the 700R4).

Years ago I put a Fairbanks low-stall converter in a slightly-modified 289 Ranchero and saw about a one-MPG improvement in the long term. Anybody offer a low-stall lockup converter?

Jack, the 700 in my GTO is setup to only lock up in high gear. I did have the lock up working earlier this year with the little 265 but, the little engine could barely handle the 2.56 with OD without the lock up.
I have not tried it with the 455. Maybe I should. It's just when I see the tach at 1,200-1,400 I am not thinking of dropping 200 more rpm.
good point though, with a 455 with little heads and cam, the lock up may help wihen not towing

It is cool when you engage the lock up. it is , effectively , a 5th gear rpm wise.

[wheelspin]

Steve,
As we have discussed before, limiting the 455's rpm @ the mph that you want to cruise at is the best single way to push the mpg into the high teens or low 20s hen used in a 4-5,000 # vehicle. Keeping the cruise rpm south of 2500 works well for my heavy Pontiacs. My 500fhp 4100 TA with 2:73 gears has delivered 17mpg @ 75mph turning around 2300rpm. My 2:93 geared 4600# GP delivers 15 mpg @ 2500/75 mph and my 3:08 geared o/drive equipped 11 second 3960 # GTO delivers 16.5 mpg @ 80 mph/2300 rpm.

[Steve Barcak]

Originally Posted by wheelspin

Steve,
As we have discussed before, limiting the 455's rpm @ the mph that you want to cruise at is the best single way to push the mpg into the high teens or low 20s hen used in a 4-5,000 # vehicle. Keeping the cruise rpm south of 2500 works well for my heavy Pontiacs. My 500fhp 4100 TA with 2:73 gears has delivered 17mpg @ 75mph turning around 2300rpm. My 2:93 geared 4600# GP delivers 15 mpg @ 2500/75 mph and my 3:08 geared o/drive equipped 11 second 3960 # GTO delivers 16.5 mpg @ 80 mph/2300 rpm.

Agreed Les. I would love to get the kind of mileage you get on some of my combos. It is just a matter of fine tuning. Am already using the right parts.
I've been a fan of 2 series gears since the early 90s. Have no desire to use anything else at this time.
I could just imagine running 80mph in an 11 second GTO and pulling 16.5 mpg. You obviously have your cars set up better than I do.