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-   -   Hopefully a Nice Stout Motor - Your thoughts? (https://forums.maxperformanceinc.com/forums/showthread.php?t=839755)

punkin 04-17-2020 03:34 PM

Hopefully a Nice Stout Motor - Your thoughts?
 
Hello all,

I'm having a motor built. Slapped a big stack of money down and the partnership/relationship/commitment has begun.

I've engaged a local builder and asked him to target a 650-700 HP motor to be used 50/50 street and bracket racing with emphasis on street. I'm really tolerant to cranky idling and less than optimal power band for low rpm driving but high compression, race gas and high temperatures is where I'm drawing the line.

The engine builder is still finalizing some of the details but here's where we are thus far.
  • CID - 530 (approx)
  • Compression - 11:1 (no more than)
  • Molnar Crankshaft & Connecting Rods
  • Diamond Custom Pistons
  • Custom grind COMP Cams Solid roller (estimating 250-260 @ .050 intake / 8deg more for exhaust w/ 110LSA)
  • Balanced and prepped to spin 6000+ RPM
  • 1.65 COMP Roller Rockers w/ stud girdle
  • Edelbrock Performer Heads - ported to 340 (round or d port, your choice)
  • Standard location Cam
  • BAM solid roller lifters
  • Manley or COMP pushrods (3/8" if possible)
  • Manley dual valve springs and retainers
  • IAII block drilled for water
  • Torker 2 (because of the hood clearance)
  • 1150 2 circuit Dominator OR Holley Sniper XFlow

As for the head choice, I've requested round ports. The cam hasn't been finalized but, if anyone had comments or suggestions in this area I truly would like to hear from you.

Otherwise, what do you think? Are the builder and I headed in the right direction? I'm sure there will be question about the rest of the car so here goes but I do realize that I'll be doing a lot more suspension and drive train work in the future if this thing really does get me to the 650-700 mark.

68 Firebird
3660 pounds (half tank of gas and me)
2800 stall
TH350 today TH400 soon to come
3:55 rear

Thank you for taking the time to read this.

shaker455 04-17-2020 04:24 PM

What the cost?
$20k?

Will 04-17-2020 05:29 PM

I really can't advise you here, but I *am* curious about something. You say "...high compression, race gas and high temperatures is where I'm drawing the line."

Are you saying you want to be able to run pump gas? Do you expect to in this combo @ 11:1 CR?

Just asking purely from curiosity.

punkin 04-17-2020 05:58 PM

Quote:

Originally Posted by Will (Post 6131418)
I really can't advise you here, but I *am* curious about something. You say "...high compression, race gas and high temperatures is where I'm drawing the line."

Are you saying you want to be able to run pump gas? Do you expect to in this combo @ 11:1 CR?

Just asking purely from curiosity.

I should have qualified that...I don't mind using higher octane fuels for WOT/track time but for getting to the car shows or cruise nights...I would like to get around without the fuel hassles. After speaking with the shop they're targeting a 10-10.5:1 compression ratio and depending on how the final cam selection turns out, this should make it for street driving.

The reason for my comment there was I've already got a motor with a lot of parts not appropriate for street use. I had considered tearing it down, doing a lot of work, replacing heads, replacing the crank (which has been turned several times), replacing rods and more. When I started adding it all up, and throw in the possibility for much more cubic inches...I decided to have one built from scratch.

I'm hoping to sell the existing motor outright (carb to oil pan, flexplate to water pump) as a runner. It's in the car, a buyer can come by hear it run and hopefully offset a big portion of my costs. I've also got a few sets of other heads, a reasonably fresh 350 short block (PMD), and some other stuff out in the shed. There's going to be a PMD yard sale in my future I think. If my budget holds out, I may spring for the aluminum block which will be nice on the front end.

If you or anyone has thoughts on the cam that would be great. The builder still needs to get me the final specs but I figured someone here might have been down this road already.

hgerhardt 04-17-2020 06:19 PM

11:1 static CR should be no problem with aluminum heads and a cam that big on pump gas. Dynamic CR is the important number.

My 428 is 11.4:1 SCR with 72cc E heads and solid roller of 248/254 @ .050, 114 LSA and runs fine on 91 octane. Just keep the quench as tight as you dare to go. Forgot exactly what mine is. I've found that has a big influence on octane appetite.

Steve C. 04-17-2020 06:37 PM

A popular 535 CID combo is 4.5 stroke, 4.350 bore and 6.7 rods.
Curious, what are your intentions or are you leaving it up to the engine builder ?


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punkin 04-17-2020 06:48 PM

For the most part I think it wise to leave it to the builder since I'm not an expert but, he's been very communicative and stated that he wouldn't order any of the critical components until he's reviewed them with me first. He's been very willing to listen to my input. He's putting together a complete list of his plans and I'm hoping to get more details in the next day or two. As soon as I have the bore/stroke I'll post it here.

Steve C. 04-17-2020 06:56 PM

Also your parts list suggests the use of a straight set of stud mounted rocker arms. Presume your intended 340 cfm without the use of offset rockers on the intake.
Correct ?

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pastry_chef 04-17-2020 07:25 PM

Quote:

Originally Posted by punkin (Post 6131387)
[*]Custom grind COMP Cams Solid roller (estimating 250-260 @ .050 intake / 8deg more for exhaust w/ 110LSA)

340 heads min. I'd want a solid roller intake lobe mid 26x @ .050.
Adding net valve lift at every cam degree, I'd target around 61 valve area.
Valve lift over .700
Look closely at http://jonescams.com/ - Mike could set you up great.

Steve C. 04-17-2020 07:59 PM

As an example and for interest here, this is very nice street build that made 650 hp with 535 cubic inches using 345 cfm Edelbrock heads with 2.250 intake valves. The cam here was a relatively mild 248 degree hydraulic roller... knowing that going to a solid roller cam you will need to add additional duration.

As in the case of this build in all likelihood the height of your intake ports on the proposed 340 cfm cylinder heads will require modifications to the Torker II intake manifold as done here. It will need TIG-welding for raised port tops in the intake, machined flat and port-matched. Nothing unusual.

https://www.hotrod.com/articles/ccrp...-alloy-indian/


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tom s 04-17-2020 08:25 PM

This IS the street section,I would not do a solid roller.JMO,Tom

pastry_chef 04-17-2020 08:57 PM

Quote:

Originally Posted by Steve C. (Post 6131488)
As an example and for interest here, this is very nice street build that made 650 hp with 535 cubic inches using 345 cfm Edelbrock heads with 2.250 intake valves. The cam here was a relatively mild 248 degree hydraulic roller... knowing that going to a solid roller cam you will need to add additional duration.

Good read Steve.
It peaked at 5400 RPM, my note above (9) was figuring he wanted 6000.

Here is hyd lobe 3318 (dark trace) vs solid lobe CR 4349, enough valve seat duration to turn 5400 RPM with 4.5 stroke. So 10 degrees more at .050.
258 @ .050
176 @ .200
.395 lobe lift.

https://i.imgur.com/NIWZhqY.png

J.C.you 04-17-2020 09:25 PM

Another vote low/ mid 260s roller should put you on the high end of your Hp goal. Bullet cams can fix u up.
Need to open up the torker ll, prefer northwind intake if you have the clearance.

tom s 04-17-2020 09:48 PM

FYI,I helping a friend that drove a 700 lift solid roller cam on the street.He lost a couple rollers and lost the whole engine.If it's going to be a true street engine I would select the cam in moderation.Again JMO.Tom

pastry_chef 04-17-2020 09:59 PM

Different people go for different things, or maybe just Chevy people do.
6900 stall.
.866 intake lift.
8200 RPM peak HP.
Drove 1300 miles on a road trip. lol

https://www.hotrod.com/articles/hrdp...g-to-be-small/

Mike Jones can design you a cam that will perform and be happy on the street.

Steve C. 04-17-2020 11:45 PM

Not here to advocate or dismiss running solid roller cams on the street, done so for over 20 years. However not long ago I had my second solid roller lifter failure with my current 505. Never on other engines. In short, Crower had no clue why and it has not been oil related or lack of spring pressure to control the valves, etc, etc.

Not long after the second failure I called Keven Crocie about a flow bench to test my cylinder heads for interest while they were off the engine. While on the phone I mentioned the solid roller lifter failure. Also mentioned it was the second time. So out of interest he started asking some questions about the failures and my engine. Now the topic turned to the spring pressure and the lifter failures. I told him I use a PAC spring rated at 240 lbs on the seat but on a Rimac bench checker they test as much as 260 lbs. Big mystery !

His opinion it was too much spring pressure for a street application. I explained to him about my UltraDyne MSP solid roller at the time with .3400" lobe lift and that it had a 30 intensity and 0.709" gross valve lift. His opinion I should work on a cam that would be less aggressive yet give me the results I desired. Net result from the conversation was to evaluate the situation further after we tore the engine down. I called Tim at Bullet Racing and talked with him. He actually agreed with Kevin. My new UltraDyne solid roller from Bullet has the same amount of intake duration at .050" but less lobe lift and able to run with less spring pressure, as low as 190 lbs seat pressure if desired.


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pastry_chef 04-18-2020 12:10 AM

Quote:

Originally Posted by Steve C. (Post 6131576)
Crower had no clue why

Crower roller lifters have a higher fail rate than years back.

Cliff R 04-18-2020 07:01 AM

"11:1 static CR should be no problem with aluminum heads and a cam that big on pump gas. Dynamic CR is the important number."

+2

Cam is smallish for the CID, static compression ratio and head flow. I've done a few 505 engine builds and use bigger cams than you are looking at, plus they were topped with High Port heads with more cross section and better flow numbers. I would re-think the cam choice and keep in mind that this will be a relatively long-stroke build with great piston speed, and it doesn't have the intake runner cross section like the better Big Block Chevy heads do, so poor to compare one to the other.

Big CID and higher compression work to your advantage with this sort of thing. A big 530 CID build with 11 to 1 will gobble up a 250/260 @ .050" cam and act like a 350 build with an RV cam in it.

The first 505 I did on an aftermarket block with High Port heads didn't have enough cam in it to make the power numbers we were looking for or take advantage of the head flow. Nearly as I can remember it was around 260/270 @ .050, solid roller on a 110LSA. It was replace with a larger cam sporting over 270 @ .050" and over .700" lift and we were nicely rewarded with another 75 HP or so and met the goals for the project.

On an engine that big the T-II will be a choke point in the system. It's a great intake for making HP but smallish to feed 530CID with 340cfm head flow.....IMHO......

PontiacJim1959 04-18-2020 08:56 AM

Quote:

Originally Posted by pastry_chef (Post 6131553)
Different people go for different things, or maybe just Chevy people do.
6900 stall.
.866 intake lift.
8200 RPM peak HP.
Drove 1300 miles on a road trip. lol

https://www.hotrod.com/articles/hrdp...g-to-be-small/

Mike Jones can design you a cam that will perform and be happy on the street.

And I bet you got 18 MPG's with it too, right? That's a race engine driven on the street, not really a street engine in my book.

TCSGTO 04-18-2020 08:56 AM

A Northwind should fit under the hood of a 1st gen Bird and would be a better compliment to a big engine like the OP is building. After the welding and porting the TII would need on that set up, cost wise you could get a port matched Northwind and have money left over. It would give the option of using a Dominator also.

With a Northwind a 14x4” filter fits under the hood of my 68 A-body with a Chevy L88 air cleaner base and a 1/2” spacer under the carb. IIRC the Northwind with the 1/2 spacer was about 1/4” lower in the back and 1/4” taller in the front than a TII with a 1” spacer. The Northwind carb flange is level where nearly every other manifold has the carb pad slope down in the front.

The air cleaner/carb/spacer/manifold can have a bigger effect on performance than a slight cam mismatch once the engine is installed in the car. Get it wrong and 20-30HP can easily be lost at the wheels.

There is a 246/252 @.050 HR in my 517 and it is pretty mild. I thought about going up about 10 degrees but the engine makes more power than the car can handle now the way it’s set up, and the power is useless on the street, so what’s the point?

Look at loosening up the converter too if you are thinking about a 260@.050 solid roller and want to get everything out of it. It would make idle tuning easier too. A 2800 stall could work but talk to some good converter people and get some recommendations.


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