[punkin]

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]

What the cost?
$20k?

[Will]

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]

Originally Posted by Will

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]

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.]

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]

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.]

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 ?

.

[pastry_chef]

Originally Posted by punkin

[*]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.]

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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[pastry_chef]

Originally Posted by Steve C.

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.

[punkin]

Originally Posted by Steve C.

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/


.

I've been looking into the Northwind but I haven't yet found anyone having this intake under a stock 68 firebird hood.

[Gary H]

Originally Posted by punkin

I've been looking into the Northwind but I haven't yet found anyone having this intake under a stock 68 firebird hood.

I put a Northwind on a 505" in a 67 Firebird. No hood clearance issues

[dmac]

Originally Posted by Steve C.

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/
.

650-700 hp at above 6500 rpm is one thing, but poster asked for 650-700 at 6000 rpm. Does that combo you listed do that? To me, building for 6000 rpm is an entirely different level that 7000 rpm. Asking for street driveability and pump gas seems to be asking a lot. . On the street, it is going to see a LOT of 2000 rpm to 3000rpm driving. This sounds like a job for a computer controlled engine?!?!?!
I enjoyed driving high compression 13:1 on the street when premium was 110 octane and octane booster was loaded with lead and really worked.

Is there a formula for how many cubic inches you need to get 700hp with 10.5:1 cr at 6000 rpm? Seems like that is the starting point, and you need to work backwards from there. Maybe a turbo, or blower????? May not even need as many cubic inches!!!!



.[/QUOTE]

[Formulajones]

Originally Posted by Steve C.

I'm confused as to the final cubic inches involved.... some posts suggest 522 and others 535. What is the stroke and bore ?

If you bring back one or more copies of a dyno sheet it will indicate the peak torque rpm and peak power rpm, and with the TQ/HP numbers to report.

The 535 combination I linked here in my post #10 with the 'same' cam, similar cylinder heads and a Torker II intake with 850 cfm carb made peak torque at 4400 rpm and peak power at a low 5400 rpm. A 1000 rpm spread.
With a Victor intake and 1,150-cfm Dominator carburetor it pushed the peak power to a higher 5800 rpm. A 1400 rpm spread.

.

Originally Posted by dmac

650-700 hp at above 6500 rpm is one thing, but poster asked for 650-700 at 6000 rpm. Does that combo you listed do that? To me, building for 6000 rpm is an entirely different level that 7000 rpm. Asking for street driveability and pump gas seems to be asking a lot. . On the street, it is going to see a LOT of 2000 rpm to 3000rpm driving. This sounds like a job for a computer controlled engine?!?!?!
I enjoyed driving high compression 13:1 on the street when premium was 110 octane and octane booster was loaded with lead and really worked.

Is there a formula for how many cubic inches you need to get 700hp with 10.5:1 cr at 6000 rpm? Seems like that is the starting point, and you need to work backwards from there. Maybe a turbo, or blower????? May not even need as many cubic inches!!!!



.

[/QUOTE]

A true 700hp, on pump, and driven regularly on the street?

Similar to dad's. He made 724 HP at a peak of just 5700 rpm. Peak torque of 764 was down at 4,000 where they started the pulls but the curve was already falling, so we never really found out exactly where it started, but even with that the spread was 1700 rpm, and it stayed over 700 ft lbs. for the entire pull, so it's a very happy engine.

This gets easier with more CI, and a good cylinder head. Which is why he went the direction of more cubic inch building a 571 Pontiac and stayed with the old Edelbrock round port heads he already had (not high ports). Now it doesn't need quite as much camshaft, and the smallish Pontiac conventional heads while hurting HP a bit, will make gobs of torque. He has no need to spin the engine up tight, makes torque everywhere, and cruises just as easy as the more mild engines I have here.

Of course it can be done with smaller CI Pontiac, but it requires a really good cylinder head and generally more camshaft, then drivability starts to become a concern for many, and what is considered a "real" street engine that you can use on a regular basis.

For comparison sake, Many of the crate 540 BBC's offered use the same (small for the engine size) Comp 248/254 camshaft, have 10:1 compression, and come with a dyno sheet, and they make right at 700 HP around 6,000 rpm, but torque is lower in the 670 range. Blueprint sells one just like this with a warranty. But it's a little easier to hit that HP goal with this engine and the small camshaft considering the heads flow nearly 370 cfm on the intake side and have excellent exhaust flow to go with it.
Doesn't have the torque curve the Pontiac will though. Personally I prefer to have a great cylinder head so I don't have to go so crazy on camshaft when I'm looking to hit a certain power goal. Makes for a happy street engine that's a little more on the tame side. Cubic Inch is your friend.

Just depends on how you want to approach it. Most street cars in here will have a hard time harnessing the torque curve a big inch Pontiac will make, or even the Chevrolet example for that matter.

[Steve C.]

John, Ken Crocie's 535 build was 11:1 compression.

Note the amount of power produced is listed in 200 rpm increments. At 5400 and 5600 rpm they are within 1 hp.

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


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[napster]

Very Impressive!!!!

Can't wait to see it in between the fenders.

Have fun with that one!!!!!!!!

[Steve C.]

Stout !





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[tom s]

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

[punkin]

Originally Posted by tom s

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

I'm not adverse to adjusting the rockers from time to time. What is your concern with running a solid on the street? Is it the spring pressures?