LT1 cam question

[Kwazrollinz28]

847 is nice, but im not ready to pull my motor again just to have it grenade sooner then i want.

[my95z28]

847 is nice, but im not ready to pull my motor again just to have it grenade sooner then i want.

pssst, you can shift whenever you want to, lol. Throw the 847 in and ported heads and short shift at 6200- 6500 if you want. That is probably the highest that is smart to go on a stock block, but then when you get in the position of bieng able to rebuild, see how high she'll go!!

[JoeliusZ28]

pssst, you can shift whenever you want to, lol. Throw the 847 in and ported heads and short shift at 6200- 6500 if you want. That is probably the highest that is smart to go on a stock block, but then when you get in the position of bieng able to rebuild, see how high she'll go!!

i thought about doing that too, but I realized thats easier said than done. If youre racing someone are you really gonna yank the power from your car the second it starts coming onto it? Eventually youre gonna want to feel the power and boom there she goes.

[my95z28]

damn, I JUST found your post on LS1tech about the 847. I think that I will read that over for the next hour or so. I can definitly see what you mean about not wanting to let out, just gotta have the will power. Or if you don't, set the rev limiter to 6500 so that you can't go any higher, lol.

[Kwazrollinz28]

lol doesnt anyone read i have PORTED heads and the 847 LOVES HIGH REVS..... As that other guys said HIGH REVS STOCK BLOCK is begging for problems.

[1fstss]

who needs to pull the motor for a cam swap? ive done a few of them in car! takes about 4 hours.
and go bog or go home!! under stock circumstances you are ok to 7K on the stock crank, just dont do it like 500 times a day!

[JoeliusZ28]

lol doesnt anyone read i have PORTED heads and the 847 LOVES HIGH REVS..... As that other guys said HIGH REVS STOCK BLOCK is begging for problems.

he was talking about for himself im pretty sure.

[BLKHAWK]

if the 847 had stock heads I could believe that, but otherwise from what i have seen and read the 847 is the one that is going to win.

There are a LOT of people running around with 847s and stock heads and its really not the best combo unless youve got happy gas to go with it. Then on top of that many dont have a good tune capable of realizing the volumetric efficiency and the result is a slug a baby cam car will have for dinner.

we made 368 rwhp through a 6 speed with an 847 with stock heads?

and the fastest 847 car I ran had ported tfs heads on it. car went 11xx's and I tuned it.

[BLKHAWK]

who needs to pull the motor for a cam swap? Ive done a few of them in car! Takes about 4 hours.
And go bog or go home!! Under stock circumstances you are ok to 7k on the stock crank, just dont do it like 500 times a day!

x2!

[JoeliusZ28]

we made 368 rwhp through a 6 speed with an 847 with stock heads?

and the fastest 847 car I ran had ported tfs heads on it. car went 11xx's and I tuned it.

GM847s peak high in hp numbers which is exactly the reason so many people think they are a good choice for stock heads.

If you want a car that peaky thats subjective, it will probably run the best times. i personally would rather have a car that might be tenth or two slower but have some down low torque to make it fun to drive on the street, and that will also last longer because im not revving it to the moon

[BLKHAWK]

GM847s peak high in hp numbers which is exactly the reason so many people think they are a good choice for stock heads.

If you want a car that peaky thats subjective, it will probably run the best times. i personally would rather have a car that might be tenth or two slower but have some down low torque to make it fun to drive on the street, and that will also last longer because im not revving it to the moon

sounds like you favor the 306 cam then. and a car that has a lunar curve "847" will not e.t like a car that has more of a static curve "306"
this is why the 306 will out run the 847 lol

[JoeliusZ28]

you are definitely right that the 306 is a good cam for stock heads but i dont know if i like it lol. It is a good match for stock head because the duration split is well matched to the airflow of stock castings.... however thats also means there are better cams to use if you intend to go with ported heads in the future.

I prefer going with a slightly smaller grind on a tighter LSA. EFI doesnt really like a tight LSA, but the small block chev definitely does. Im very happy with my cam so far and cant wait to see what itll do with a good tune this spring, but i do think i could have gone bigger. Here are my top choices (not in any specific order) for stock head, stock bottom cars:

Comp 224/230 ground with a tighter LSA and some advance
AI 226/234 110 LSA, advanced (what i have right now)
AI 230/238 110 LSA, advanced (what i might switch to later on)

Im also compiling some results on the Comp 230/236 which i havent really formed an opinion on yet - there are a few variations of that cam (xe and xfi) and I have seen a lot of inconsistent, outlier results in both directions with them.

on a daily driver I would probably use the same cams just a little wider LSA and maybe without the advance for driveability and better vacuum.

[BLKHAWK]

you are definitely right that the 306 is a good cam for stock heads but i dont know if i like it lol. It is a good match for stock head because the duration split is well matched to the airflow of stock castings.... however thats also means there are better cams to use if you intend to go with ported heads in the future.

I prefer going with a slightly smaller grind on a tighter LSA. EFI doesnt really like a tight LSA, but the small block chev definitely does. Im very happy with my cam so far and cant wait to see what itll do with a good tune this spring, but i do think i could have gone bigger. Here are my top choices (not in any specific order) for stock head, stock bottom cars:

Comp 224/230 ground with a tighter LSA and some advance
AI 226/234 110 LSA, advanced (what i have right now)
AI 230/238 110 LSA, advanced (what i might switch to later on)

Im also compiling some results on the Comp 230/236 which i havent really formed an opinion on yet - there are a few variations of that cam (xe and xfi) and I have seen a lot of inconsistent, outlier results in both directions with them.

on a daily driver I would probably use the same cams just a little wider LSA and maybe without the advance for driveability and better vacuum.

efi dosent like a tight lsa eh? explain this please.

your saying the duration split on the 306 matches the ie ratio on stock heads? you might wanna re-do your math do you know what stock head ie percent is?

[JoeliusZ28]

I was merely referencing the fact that cams with overlap usually dont like to idle at stoich, which is what most EFI systems will try to do, per their design for emissions purposes. Not that you cant make it work because obviously many people including myself are doing it.

stock flow numbers are in the ~200/150 ballpark, but less than 75%. The exhaust side of the LT1 head is where the restriction resides, thus the benefit of of a split duration favoring the exhaust side and also why head porters do most of their work there. The intake side always flows more (the size of the valve alone indicates that). But air in is only as good as air out.

My opinion is that the split of the 306 is a little bit overkill, but I wont deny it is a proven cam.

and I know this isnt your first rodeo with this stuff, your just nitpicking me

[MunsterZ28]

hech we made 500rwhp with an a4 car with a hotcam and a 150 shot.

holy cow batman! lol i guess she does have more potential then i thought