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Awesome budget 400 sbc block builds

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400 gmc
14K views 23 replies 11 participants last post by  6426yy 
cheap 400 I built for a friend. 1978 monte carlo, 20 plus miles to the gallon when right foot is restrained and 14.1 1/4 mile times with 2.73 gears and white wall radials.turbo 350 with shift kit,stock converter.
Bone stock short block rebuilt with cast pistons and static balanced,stock heads.Mild 430 lift flat tappet hydraylic cam,street master manifold, 625 carter carb,1 5/8 primary headers,2 1/2 " dual exhaust not mandrel bent. no where near 400 HP,but a tonne of torque. tire melter
 
377 = smaller engine ,so less torque at a higher RPM.Its all simple math,,,start with what you want,add in what you have and see what it will take to get you to where you want to go.EG: If I have 400 rwhp in a 1970 Nova,set up with 4.11 gears,matching transmission to engine,the car hooks well( assuming drag race) has traction bars that are tune able, the car weighs 3500 pounds or less with driver and fuel,ready to go,he has slicks,this car will go 12.0s.

to figure out what your car will do,add or subtract 1/10 for every 10 hp up or down.If you use a (Winderupper} you will need gearing to accommodate the different powerband.for every 100 pounds difference add or subtract 1/10th.If your car is not as good at hooking as the nova,expect slower times.If you do not use slicks,expect 13s.If you dont need slicks expect slower,much slower.Add 3/10ths for exhaust system on small blocks.This is not an accurate guide but it will give you an idea where you might be or where you might get to with some tuning.
 
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