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Building 302 from a 350 block

9K views 31 replies 13 participants last post by  halftonhotrod 
#1 ·
Hello,

I've been doing some readings on this forum for a while now but I'm a first time poster.

I was wondering if anyone knew of a build that I could follow online (or had any information) about making a 302 from a 350 4-bolt block. New they're only ~$850 so I figured that's not too bad, because a used block (to make me feel better) would have to be gone over by a professional before I put it in the car, so I figured that negates the savings of a used block.

I know I can make more power with a 350; please don't comment on that.

This motor will go into a car weighing ~2300lbs so I want it to have an rpm range of close to 8000; and a horespower rating of around 350 max; using a carbureted set-up because I don't want the extra cost and hassle of having a large wiring system. Probably use a large journal crank in the block as oppose to the bearings that act as spacers for the small journal unless anyone has an idea as to why that would be a bad approach.

I'm just having trouble determining parts that will work well with one another; ie rods/pistons/valvetrain.

The car will most likely end up with a T5, and I'll determine a rear-end gear from there; probably something around a 3.6 maybe a little higher?

Any help would be greatly appreciated!
Thanks in advance,
Tony
 
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#28 ·
The 450HP 302s were heavily prepped. 12.5:1 compression, off-road cam, heavily ported heads, specially designed headers to go with the cam and cross-ram. They had been making 425HP with the LT1-style dual plane and 780CFM carb. The 302 is a wonderful story, but we can't make it out to be better than it was. Traco-built race engines made for Roger Penske dyno'd at 458HP on the sheet I saw in a book about the cross ram. I am sure they must have kept something in their pockets.
The little 302 was indeed under-rated, because it wanted to go way past 5800RPM. Check out this article where they built a DZ302, L76 327, and LT1 350.
http://www.superchevy.com/technical...p_0909_chevy_small_block_testing/viewall.html
They all made just a shade over 350HP. This makes sense, because the heads were practially the same, and the cams were practically the same. The change in displacement just moved around what RPM the peak power came on at.
 
#29 · (Edited)
Sure we had our secrets, but its silly to build a 302 with only 350 hp today unless its a concoarse car!!! when a 327 0r 350 can put down more horse power and more torque cheaper!!! and at penske we dynoed a 302 for Mark Donihues car for trans am at 475 hp!!! and that was still a cry from max hp because of the durability issues from the rigors of long hrs of non stop raceing !!! I have no Idea what the max hp on the little 302s would be! I dont think any one has taken them to the limit!!! And when you bought the 302 DZ package the headers were packaged and in the trunk at some dealers! It was up to the owner to install em.

Jester
 
#30 ·
http://www.z28camaro.com/oldrel.html

Check out the specs at the bottom of the page I just posted! Youll like the read and its late and Im tired, So if I already posted it on here (LOL) you can LOL :D

Stock champion in 2005, 302 single 4 barrel 780 cfm, (NO CROSS RAM) .480" solid cam no head work (maybe a few little legal tricks: If its not against the rules do it !!!), 456 hp :mwink: !!!

Jester :thumbup:
 
#32 ·
I say build it if u want it thats what makes this hobby interesting i drove my buddys 66 elco with 3.08 gears and muncie m21 it had a 302 with 305ho heads old famous z28 intake and mild street cam and against most beliefs it had decent tq and pulled strong up to 5 to 5500k it was cool to tell people it had a 302...but that was about it. They did put henrys 302 in f150s.....4"x3" motors will make ok tourque with mild cam but building a mild street 302 u r sacrifcing some h.p. &grunt just to b differant . I know thats not exactly whats the type of 302 that was origially asked about so hopfully nobody jumps on me.
 
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