302 based or 351 based combo?

silverbulletGT

New Member
Nov 21, 2002
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Alright guys guys this will be a little long so bear with me! I have a 89 coupe that I bought with the intentions of just having a fast street car. The car was built went I bought it. I paid $8500 for it about 2 years ago. It has a lot of good parts. Im not going to list EVERYTHING but heres the basics a 306 with forged internals (unknown what man. but aftermarket). Vic. Jr heads, holley intake, custom cam (unknown specs makes power to 7500rpm), SVO rev extender,MSD morroso pan, 6AL,NOS big shot wet kit 200shot. The car has upper and lower control arms, k member. Has been 10.70s in the 1/4 on slicks.


The car is a 4cyl conversion and the wiring is a mess. I tried to fix it and made it worse I have no idea what this guy did. The fuel system is also a boogered up. Like most EFI foxes it surges at idle. (have tried everything) I want to start drag racing again and my goal is to run 9's on DR's. Im not going to get there with this combo and a stock block. So instead of pushing it until I start hurting parts I want to tear everything out and start over. Im looking for a simple set up that will be reliable easy ti diagnose and consistent at the track. I have had turbo cars and blower cars in the past and they all gave me problems, they were always breaking down.

I want to build a carbed 408 (69 block)with 13:1 compression reuse my vic jr's with some heavy porting and a 200 shot or bigger from a plate kit. Im not going to go into great detail here because this is already too long.

My thought is that if Im going to pull my motor why not go bigger. I plan to sell all my 302 based stuff that doesnt carry over to supplement the cost of the build. My friends think Im nuts to tear apart a 10 second car but with the power Im making the motor's days are numbered (have not sprayed in almost a year:nonono: ) so why wait for a catastrophic failure that might damage parts that I can get money for. Most I have talked to say stay EFI and built a 302 based stroker with the new boss block.

I need some outside opinions.
 
what kind of budget are you on? i mean, ive personally never done a 351 build but i can imagine a stroked 351 will cost a bit more because its not as popular... just a thought...if money is no object id say go for it cause it will definately put down more power...all motor is safer than forced induction
 
Money is an issue but Im guessing my 408 will cost about 5K to build w/ me doing the labor. A boss block alone is 2k with machine work (more if I cant reuse my rotating assembly) plus at least $3500 for a used blower.
 
how much power are you looking to make.
a 351 block is considerably stronger than a 302 block. so depending on how much power you want to make , you may not need an aftermarket block with a 351.
 
It all depends where you want to be. I'm in the process of building a 408 right now. Not much different than a 302, don't have to change too much or spend too much if you want to. Mines going to be a drag car so I've gone a little overboard with a Dart 351, TFS CNC HighPort heads and Eagle forged internals. It's gonna cost but safe for the long run. I'd do the 351 conversion if I were you.
 
I'm just going to throw this out there....

If you have wiring problems due to the 2.3 conversion, you should take stock of what UNMOLESTED harnesses you have, then go hit the boneyards or search Ebay for any unmolested harnesses you may need. Finish the conversion first. Basically un-do everything that was done and put as much of it to stock as possible. Harness and sensor wise.

I know it may sound like a PITA, but it will be worth it in the end.

Mine was a 2.3 conversion when I bought it, I spent the better part of a year finishing the conversion so that the car was 100% 5.0. I replaced all the engine harnesses, cleaned up all the connectors...I even went as far as to upgrade the 2.3 suspension to 5.0 suspension....only to upgrade to aftermarket later on.

The reason I did it was because I kept running into issues where I would order a part, or go to replace something and I always asked for 5.0, and sometimes it was the wrong part. It got to the point that when I went pricing things, I was unsure if I should look up 2.3 or 5.0. So I finished the conversion, knowing that I would eventually be replacing a lot of that with aftermarket stuff anyway. But it made modifying it SO much easier.

As it stands right now, there is NOTHING in this car that is 2.3 specific.

It sounds like a stupid waste of time...but in the end, it made my life a WHOLE lot easier.

Just food for thought.
 
what kind of budget are you on? i mean, ive personally never done a 351 build but i can imagine a stroked 351 will cost a bit more because its not as popular... just a thought...if money is no object id say go for it cause it will definately put down more power...all motor is safer than forced induction


Stroker kits cost about the same...the differences are in the intakes and headers but even that isn't so much more expensive that it would blow a person's budget. Personally if i had a bone stock 302 i would be looking at doing a 351 swap, but i've already got so much for my 302 that i'd have to start at square 1 with the 351. More cubes, stronger block...but also more weight and less engine space and hood clearance. It all depends on what you want.