budget 403 build

[mike87442]

I am looking to build a low dollar(if possible) 403,I am going to use a stock bottom end and 7a heads,does anybody have any ideas on what cam etc to use. My car is a 87442 with a 2004r and 3.73 rear

 

[FE3X CLONE]

We did something similar to my brother's 403. His engine specs are below:

First engine:

403 bored .030" over
Stock crank
Stock rods
Stock cast replacement pistons

7a heads, untouched other than a 3 angle valve job
Stock rockers

Crane Cams hydraulic flat tappet cam. Forget the exact specs but I think is was something like a 218/226 @ .050, .496/.512" lift, 112LS

Edelbrock Performer intake

750cfm Speed Demon vacuum secondary carb

1-3/4" headers with 2.5" duals, H-pipe and Dynomax Ultra-flo mufflers

TH-2004R trans with 2200 stall and 3.73 rear gears.

His best time with this setup was a 13.6 @ 101mph or so.

But on his third run, something happened and he ended up with a snapped camshaft, broken timing chain and the teeth on the crank gear stripped off and laying in the oil pan. All after just 1500 miles. 🙁

Second rebuild, same as above except:

Installed ARP main, rod and head bolts
Changed camshaft to an Ultradyne 221/227 @ .050, .485/.485" lift, 112 LS
3000 stall converter
Performer RPM intake

Best run with this setup was 13.2 @ 102mph. We never really "tuned" the car or messed with making it any faster with what it has but it really should be a high 12 second car.

 

[Bernhard]

Andrew were you able to save the bottom end of the 403? What did you do to the 2004r to make it live behind a 403? There is lots of good 403 engine tech on Realoldspower.com Do a search many have done what you want to do. Good Luck.

 

[FE3X CLONE]

Andrew were you able to save the bottom end of the 403?

Save? Nothing happened to the bottom end of the engine when the cam/timing chain snapped. We just had everything pulled back out because he upgraded to a BHJ balancer and so we had everything rebalanced. That's when we decided to upgrade to the ARP hardware.

On a side note, if you go to a GM dealership and ask for a 403 balancer, they will give you the wrong one. I don't know why but the dealership and even most parts stores list the 403 as taking the small 260/307 Vin y balancer and not the larger balancers with the outer ring and rubber isolator. We think this could have been part of his problem in the beginning. Haven't had a problem since switching to the BHJ.

What did you do to the 2004r to make it live behind a 403?

He originally wasted $1200 on a brand new, crappy TCI TH-2004R that was *SUPPOSED* to hold up to 450HP. It was slipping within a few hundred miles. By then I was into the restoration of my '87 and had decided to go with a 6 speed so I gave him the Art Carr TH-2004R I had behind my 455. It's been holding up just fine for years. I bought that trans back in 2000, so I can't remember exactly what all was done to it. Was supposed to be rated at 800hp/650ft.lbs.

 

[Bernhard]

Thanks for the reply Anderw. Glad to here that the bottom end was fine. Bernhard