more power for my 403 smallblock

[mutzi]

hi, i´m a new user. i´m from germany.

i buy last year a 1978 olds delta88 with an 403 cid.
the engine is stock and i need more power for my car.

i read the compression of the stock 403 heads are the problem.
the edelbrock heads to expensive. i read in the internet: when i use 1972 olds 7a 350cid heads than i have more compression.

what i need even for tuning:
- is the stock rochester 4bbl carb. ok or is the edelbrock 1806 avs thunder 650cfm better?
- is the stock intake manifold ok or is the edelbrock 2711 performer better?

thanks you have really helped
mutzi

[1971olds350]

Originally Posted by mutzi

hi, i´m a new user. i´m from germany.

i buy last year a 1978 olds delta88 with an 403 cid.
the engine is stock and i need more power for my car.

i read the compression of the stock 403 heads are the problem.
the edelbrock heads to expensive. i read in the internet: when i use 1972 olds 7a 350cid heads than i have more compression.

what i need even for tuning:
- is the stock rochester 4bbl carb. ok or is the edelbrock 1806 avs thunder 650cfm better?
- is the stock intake manifold ok or is the edelbrock 2711 performer better?

thanks you have really helped

mutzi

heads-cam-intake 1-heads get #7 heads get them ported, get bigger valves etc. 2-get a good cam from mondello 18-20 thru 22-25-10. 3-put a edelbrock intake rejet the carb you have and i think other than if the enigne in good running condition thats all i would do

[Redog]

If the hood clearance isn't a problem, put an eldebrock 7111 mani on it.

Jegs sells a complete kit for this. Get you're hands on #5 thru #7 or #7A heads. Be sure the #7A heads are from 1972. I can post casting numbers later. Put in hardned valve seats, bolt on and go

[Redog]

Don't know if you have to have emissions but if not:

http://www.jegs.com/i/Edelbrock/350/7111PK/10002/-1#

And your heads and your done

[Warhead]

Originally Posted by mutzi

hi, i´m a new user. i´m from germany.

i buy last year a 1978 olds delta88 with an 403 cid.
the engine is stock and i need more power for my car.

i read the compression of the stock 403 heads are the problem.
the edelbrock heads to expensive. i read in the internet: when i use 1972 olds 7a 350cid heads than i have more compression.

what i need even for tuning:
- is the stock rochester 4bbl carb. ok or is the edelbrock 1806 avs thunder 650cfm better?
- is the stock intake manifold ok or is the edelbrock 2711 performer better?

thanks you have really helped

mutzi

Guten tag, Mutzi.
Compression will wake up your 403.
#4, 5, 6, 7, or 7a heads will work well. These have 68 cc chambers that will give you 1 point more compression. These early heads come with smaller intake valves, but larger exhaust valves. You should have 2 inch intake valves installed in them by a competent shop (you can use the ones from your current heads), to reap full benefits of the early style heads.
You will also need to have the head bolt holes opened up to 17/64 inch, because these heads used smaller head bolts. Also the 3rd head locator pin hole must be opened up to the size of the other 2, to be able to mount these on the 403. Use 403 head gaskets.
Keep the stock carb, you may want to put thinner rods in the secondary side, make sure you have full throttle, 36-38 degrees total timing (all in by 3000 rpm).
By the way, the Edelbrock heads have 77 cc chambers that will not help compression, and you can not run the factory mechanical fuel pump on a 403 with the Edelbrocks.
Where in Germany are you located???
Bitte
Jim in Phx.

[dan2286]

Nitrous Oxide always does the trick! Just kidding, that might hurt something.

[380 Racer]

AAAAAhhhh Jim......17/64ths?

[1971olds350]

put some headers, x-pipe and flowmaster 40's exhaust. also if you lower intake temp from 220f to 140f by getting cold rammed air from outside instead of underhood on a 300hp engine you'll increase horsepower to about 330hp more or less.all that and my formula of heads-intake manifold-cam. if you pick everything out right you'll engine will have about 300 to 350 horses or more. good luck

[mutzi]

hi and thanks olds-guys,

when i summarize all your reply than i list follow parts:

- the stock rochester 4bbl carburator with thinner rods (is that needle? what size?where i can order this rods?) in the secondary side
- the edelbrock performer intake manifold (iddle -5500rpm)
- hydraulic camshafts mondello (whitch? JM18-20 or JM20-22 or JM22-25 or JM22-25-10?)
- 403 head gasket (stock?)
- Olds 1972 350 Heass ID/Code #7A 64cc Casting Number 409147 (where can i buy or can i use remanufacture-heads) with a 2inch exhaust valve.

what your says about now - runs the engine then?

warhead i´m from magdeburg - eastgermany -> 100miles west from berlin.

[Wireman134]

Originally Posted by mutzi

hi and thanks olds-guys,

when i summarize all your reply than i list follow parts:

- the stock rochester 4bbl carburator with thinner rods (is that needle? what size?where i can order this rods?) in the secondary side
- the edelbrock performer intake manifold (iddle -5500rpm)
- hydraulic camshafts mondello (whitch? JM18-20 or JM20-22 or JM22-25 or JM22-25-10?)
- 403 head gasket (stock?)
- Olds 1972 350 Heass ID/Code #7A 64cc Casting Number 409147 (where can i buy or can i use remanufacture-heads) with a 2inch exhaust valve.

what your says about now - runs the engine then?

warhead i´m from magdeburg - east germany -> 100miles west from berlin.

Hello, Mutzi, Heim here. You may or may not need or want the smaller secondary rods for the Q-jet carb. The smaller the dia. the richer the mixture will be. Secondary rods with small dia. size around .0550" are good for most mid sized street V8's. You may want to change these when you tune or dinotune the engine. Parts available here:http://www.gesslerheadporting.com/me...7!OpenDocument
The Edelbrock Performer is considered a stock replacement manifold by most, but will support 300-350hp. The RPM manifold would give a increased power in the 1500-5500rpm range. This manifold is 2" taller than stock.
Number 7 heads: ream the bolt holes for 1/2" head bolts,modifying the line up pins and water jackets to fit the 403 block. They will give a 8.5 cr with a 403cid .040" head gasket and stock dished pistons. The Mondello JM18-20 or JM20-22 would be my choice for a low compression 403, the latter one with low gears. The 2" 403 intake valve installed in the #7 350 heads would work well. If you can get these heads in Germany, I don't know? They are all over in the US here:http://minneapolis.craigslist.org/pts/921776206.html

Alveterzane

[Warhead]

Originally Posted by 380 Racer

AAAAAhhhh Jim......17/64ths?

Sorry, 17/32nd's. oops...QUITE embarrassing. Thank's Nick.
I was referring to the secondary metering rods. Maybe a CC or AU rod with an A-K hanger. If you mill the #7 heads .030, you should be able to get to 9.25 compression. Beats the 7.7 or so from the factory.

Olds 1972 350 Heass ID/Code #7A 64cc Casting Number 409147 (where can i buy or can i use remanufacture-heads) with a 2inch exhaust valve.

You want a 2 inch INTAKE valve, like the 403 heads have.

Mine frau has family in Hamburg.
She's going there in January.
Jim in Phx.

[Cratethis]

Do you know if your motor has the closed webs? If it does you might not want to do a lot to it. Most 403's from 77 to 79 have the closed web design and have a tendency to overheat in stock form and any boring is really out of the question.

My two cents would be either put work into a good 350, or move to a big block.

[380 Racer]

Originally Posted by Warhead

Sorry, 17/32nd's. oops...QUITE embarrassing. Thank's Nick.

Actually I should be apologizing to you.......it was the ROP coming out of me .

[mutzi]

thanks guys, now im looking for parts.

thanks wireman134 - but the heads been sold.

hi warhead, i have in hamburg a good friend, maybe we can meet together when you stay there.

now is weekend - i look monday in the forum.
bye have a nice time

[mutzi]

hi cratethis,
i understand your message what is web or webs?

[mutzi]

hi 1971olds350,
i dont understand the red part of your message:
if you lower intake temp from 220f to 140f by getting cold rammed air from outside instead of underhood on a 300hp engine you'll increase horsepower to about 330hp more or less.

[joe_padavano]

Originally Posted by Cratethis

Do you know if your motor has the closed webs? If it does you might not want to do a lot to it. Most 403's from 77 to 79 have the closed web design and have a tendency to overheat in stock form and any boring is really out of the question.

"Closed webs" ? Are you referring to the windowed main webs (which have nothing to do with cooling) or the siamesed cylinders? Despite what Mondello may say, no one has been able to provide proof of the existence of a solid main web 403 block in the last three decades. Assume they are all windowed, which is no reason to not build a 403 unless you plan to make crazy amounts of HP (note that the Chevy LS series blocks are also all windowed).

As for the siamesed cylinders, all 403s have them, which is how Olds got a larger bore than the 455 in that SBO casting. Yes, cooling is not quite as good, particularly in the middle two cylinders of each bank, but that alone does not condemn the block, as many 400 Chevy motors have shown.

[Wireman134]

Originally Posted by mutzi

hi 1971olds350,
i dont understand the red part of your message:
if you lower intake temp from 220f to 140f by getting cold rammed air from outside instead of underhood on a 300hp engine you'll increase horsepower to about 330hp more or less.

This is referring to cold air density. Being more oxygen rich. I believe as a rule for every 5F degrees drop in air intake temperature there is a gain of 1% in horsepower. Keep in mind what fuel you have available. For you to run a 9:5:1 static compression ratio you may need to have RON 98 gasoline equal to our 94 RON+MON/2 fuels in the US. Use this to figure your compression ratios prior to building


http://www.projectpontiac.com/ppsite...nt/view/16/30/

[Warhead]

I read that it was 1% for every 7 degrees.
He may be able to get about 10-15 hp this way.
That also works for the fuel system (I am not sure what the % is), fuel is more dense when cold.
Jim

[Warhead]

Originally Posted by 380 Racer

Actually I should be apologizing to you.......it was the ROP coming out of me .

I am glad you caught that!!!
No need to apologize for being an ROP crazyman anyway.

[joe_padavano]

Originally Posted by Warhead

I read that it was 1% for every 7 degrees.
He may be able to get about 10-15 hp this way.
That also works for the fuel system (I am not sure what the % is), fuel is more dense when cold.
Jim

Actually, the rule of thumb I've always heard (including in the Roe book on Qjets) is 1 horsepower increase for every 7 degree (F) decrease in inlet temp.

[380 Racer]

Being a bracket racer, I keep track of weather conditions so as to know what the car is ging to run. My weather station registers temperature, humidity and barometric pressure. It then tells me the adjusted altitude from those three. I would be very surprised if a small (<20*) by itself will make much of a difference. Most usually humidity plays the most important part. Unless there is a front that moves thru.

Carry on.