Wrapping up a port and polish job for this guy that I know, and I wanted to show some of you guys what a typical Grand National cylinder head looks like from the factory before its even touched. From what I was told, these particular heads (untouched) brought a full weight turbo regal to a high ten second pass, but we're talking bigger turbo of course, not a bone stock configuration. He didn't want that much work done on the exhaust side, he's just looking to run an 11.00 to 11.50 comfortably, without pushing it too hard (no roll bar). He shouldn't have a problem now. And some of you guys thought that "our" cylinder heads were horrible from the factory....

 

i noticed your sig. says original 305 w/t76 ... what exhaust a/r are you using an hows your spool up ? an what else has been to the 305 ?

 

Need to update that sig, because those headers and turbo have found their way on my '84 Trans Am project. .96 a/r, the GTA ran the stock LB9 bottom end., heavily ported 882 heads; 1.94/1.50 76cc, fully siamesed and ported TPI setup, cam was custom, 3500 stall (felt a little tighter), 3.42 posi. There was way more in that setup to run faster with more injector, but duty cycle was pegged with what I had to work with. Lifted a head quite a few miles away from the house last time out, and was too aggravated to even look at it when I got back....

 

Yeah the LC2 heads make a stocker 305's look good especially since the cyilnder volume on the 305 is the same as an LC2. (yes bore and stroke are different.) I still think the LC2 got a better intake power potential wise though. How much boost was "low boost" if you don't mind me asking. Did the 882s make it soggy, and what was the cam size roughly?

 

That cam, although did do its job, was based on what the turbo regal guys were running. I was trying to turn an LB9 into an LC2 at the time, and wanted to experiment with similar cams. The bore and stroke of both engines seemed pretty close (3.73" Bore 3.48" Stroke vs 3.80" Bore 3.40" Stoke), and I wanted to emulate their Erson 208/208, as it had good idle manners, yet pulled extremely hard, so I had CompCams make me one slightly larger than that because of the larger intake valves in the 882's, but overall it was pretty much based on that camshaft. Why would I mind you asking??? Injectors were already pegged at 14-psi of boost, and I opened up the 882's substantially. Not that soggy at all, just a little laggy as I should have went with the TC series. The stall and gears definitely helped....

 

Street Lethal, is there a build thread for that setup somewhere?

Your last response was kind of hard to interpret, the first 2 sentences were kind of like "I was doing it wrong" and the last 2 are like "It worked mostly well"

 

I just reread what I wrote, and it does sound like I was implying that lol. The build for the '90 GTA was/is getting a forged 355 that I pulled out of a Z28, so I didn't really care what was going to happen to its stock LB9. The 355 is still sitting on the floor in the garage with the GTA. The stock engine though was just being used as a mock up for the turbo system, but when we finally got it together, after getting egged on to do it, the 882 heads that I was working on for the 355 were installed on the 305, and then I ordered the cam. The TPI setup was already siamesed, just like I did for the '84 Anniversary thread. All I had to work with at that time though were a set of 30-pound Grand National injectors, which is why boost was kept to a minimum, not that the 305 would have lasted that long anyway. I didn't really mean to imply that I was doing it wrong, just that an engine isn't always an engine, and I should have selected the cam based on the small block chevy, not V6 Buick. The 305 Chevy has such an advantage over the 231 Buick, that basing everything on that latter would only slow it down. It did in fact work out well though, but if I had to do it all over again with the 305 (and I am, with the '84 Anniversary build thread), I'd of gone with a much larger camshaft, a la 224/230. That is the whole reason why I started that other thread, Chronicles of a Nine Second 305. Plenty of updates coming in that one....

 

Heh... I didn't connect you to that thread, I think I posted early on in that thread how similar that project is to mine, but honestly I haven't kept up with that thread since work and life caught up with me. I'll have to find some time to go back through it to see what I was thinking at the time vs where it's at now....