84 4+3

Hey guys. So my research has evolved significantly since I had asked about the gmpp vortecs. (And for good reason I suppose)

My original plan was to fix the misfire and then build from there. A snag came when I realized the problem was actually caused by the aftermarket intake manifold. Now that aspect is already set, it's either getting a ported out stocker or an aftermarket that isn't foobar...

Now the out come of that will determine if I actually do what I'm thinking about or not. So, my plan was this. Do a set of heads, aluminum. I've been looking at modern port and chamber design in the 195cc range and a chamber of around 64cc. Using rough guesses of the block itself and a .015 head gasket this puts my quench at. 04ish and the static compression at about 10.25:1. Head flow numbers are 254intake 180 exhaust at .4 and w273intake and 206 exhaust at .5. Roughly that is. That's just the upper numbers from one of the heads I was looking at. That particular head retains really good port velocity for a 195 as well. (Also what I've been looking into lol.) I have also decided to ditch the egr setup as I don't really think I'll need it...

For the cam, I was looking for something relatively mild actually. Something around 228/235 ish at .05 adv. around 277/285 on a 112-116 lsa but with low lift, around .5 or less because I don't want a ton of strain on the top end. I want it somewhat tame...

So my goal was around 300hp to the wheels, plus or minus 30 or so and an effective operating range somewhere between 1500 and 6500rpms. I don't think this is unobtainable with a combo like above and good tuning but what has me nervous is the dynamic compression/ability to run pump gas... from what I was able to gather, for a low to mid 6k engine you'll want compression around 10:1 to match a cam in that rpm range nicely. That's fine. But the dynamic compression I'm getting with those types of cams is putting me around 8:1. Depending on who you ask that seems safe or im asking for trouble.

I'm curious what everyone thinks of doing something like this and if it's even going to work like I want it to. My plans for the car are a cruiser with some spirited driving and once everything is sorted, some passes at the strip on occasion too. Getting 93 around me is pretty easy as most of the stations near me are updating their pumps to offer it for whatever reason... is this something that is going to get me a fun cruiser like I think or am I better off saving coin and putting it toward something else? Any and all feedback is welcome.

Kevova

Are you planning on using crossfire?

84 4+3

That was one of the design constraints I had to consider. Yes I plan on retaining it. Yes I plan on ebl flash as well.

jim2527

https://www.corvetteforum.com/forums...cfi-build.html

84 4+3

His thread is one one of the ones I based my design around. I was in contact with him earlier in the year too. While I don't know his cam specs I do know his build is a bit more than what I was shooting for. But a very informative read.

Hot Rod Roy

Curious what aftermarket intake manifold you were using, and what was the problem that you discovered?

84 4+3

Renegade. Casting shift/error on the runners on the 1,3,5,7 bank. Post 144 here. Basically the roof of the runner was hit or miss if it was going to seal.

84 4+3

Any other thoughts? I'd like to start gathering parts so when school is done I can get it done. Life is too short to drive boring cars and I really want to do this while I'll still have some time to enjoy it fully you know?

I think I'm going retrofit roller. I don't need some super crazy track monster, I'm just shooting for a street machine that will occasionally go down the strip. I was looking at the 280xfi but honestly I think it'll be too much for mostly street. I don't know. I'm trying to teach myself but sometimes you need to ask for help.

ex-x-fire

I'd start my build with a good used vortec 350, roller conversions are $$.

84 4+3

I have a couple laying around. My only problem is that by the time I get one up to snuff it's more or less the same as just doing the conversion. (Since there is nothing wrong with the the engine in the car...) Aside from that, it only hurts once but I get it. The stupid timing chain cover bothers me. I only built one and it leaks from the balancer. Honestly have no clue why. However I'd have a 1 piece rear main seal and most likely a 4 bolt block so it honestly would be the better way to go long term but... I don't know. Maybe if I had a good vortec short block.