350 TPI - cam specs to be 210/216 degree duration .440/.454 in. lift

* Heads - Trick Flow Super 23 64cc - 195 cc intake

Now I know the 180cc intake heads would be more ideally suited for a mild TPI engine, but my question is would the 195cc intake heads hurt performance (velocity)? I will also be using the larger TPI base and runners.

I'm considering the 195cc for the long run so I can build upon them when the block needs rebuilding (to 355, or 383). Just want to make sure I won't suffer by having heads with intake side bigger than TPI can hang with. If I could get the complete Trick Flow kit with 180cc heads, I'd probably just snag that.

Suggestions?

 

THe 195s will slow velocit and cylinder filling on a 355 but if your goal in the future is 383 to 406 id go with them!

 

i wouldnt use the 195cc heads unless ur building a 383 etc as stated. and u would have to upgrade the TPI.... tpi wont flow enough for the 195cc heads velocity.... the 195cc heads could work beautifully on a 355 if you were reving to 6500-7000.... but we all kno a TPI cant.

195cc heads on a 355 with a HSR/mini ram/LT1 and a cam with about 230-240degrees would work nice. thing would rev to the moon.

the 180cc heads will make better power on a 355 than the 195cc ,with a lower RPM power range that the TPI would like better and can still be used on a 383. the 383 will just create peak power alil lower in the RPM ranges but will make a butt load of tq with the 180cc heads down low, also with the TPI its gona burn tires!. ive seen alot of 383 motors make 423hp with stock vortec 170cc heads. i wouldnt expect to make more than 450hp with the 180cc tho.

 

I've got 195cc tfs heads on my carb'd 355, the cam is just a little bigger than yours at 215/215 and .530"/.530" with 1.6 rockers. performer rpm intake with a 600cfm carb(I guess the runners are similar in length and c/s to an hsr). So far I've gone 12.3 at 109.5 with it, maybe I'll pick up a bit when I switch to an efi singleplane.

It makes excellent torque in the midrange and I generally shift it at 6k, it seems to flat line from 6000-6300 then fall off. The off idle torque isn't really there, but that's hard to notice with any sort of decent torque converter. The power really starts to come on at 3000-3500.

If you are planning on switching the intake in the future I'd go with the 195's, you would still make decent power with the tpi, just not quite as much torque.

 

I don't think it will be too much cylinder head. I don't have much experience with the Trick Flows, but if they move air at low-mid lift areas like the AFR's do, you won't have a problem. Your cam is fairly small though. I'd consider stepping that up since your doing the intake upgrades. Maybe a 218/224 XE. Good luck!

 

the TFS heads are nothing crazy.... well not for the money. they flow alil less than my patriot 195ccs.... about 260cfm at .6 lift and the exhaust is about 183cfm. my patriots are around 270cfm and only cost 880$ BLAH!

best 195cc head would be the AFRs.... street eliminators are flowing sumthing like 300cfm lol insane... but cost 1400 cheapest. i wont spend that much

 

Port injection like TPI isn't as sensitive about the port velocity as carburetor because it doesn't rely on velocity to meter or atomize the fuel.
You'll be fine depending on your cam specs.
Look at the specs on your cam card where it shows the intake valve opening event.
If your intake opening at 0.050" is somewhere near or at zero 0* BTDC, or a little negative like -2* BTDC then you'll be fine.

 

Large ports don't have as much effect on drivebility as most people think. Large ports can be just as street friendly on a smallish motor as a normal sized port, if you use the right cam. Go for the 195cc heads, and just pick the right cam for your TPI setup/driving conditions. The large ports may or may not really help with a stock TPI (over the 180cc versions), but they won't hurt anything either.

Look at the factory LT4... 350ci, 195cc ports, and a cam just a hair bigger than the stock LT1 cam. It was just as user friendly as the LT1 was, just made more upper rpm power. Low and midrange weren't noticeably different.

Same is true for the LS1, as it came stock as a 346ci with 200cc ports, but I didn't want to use this as an example because its a totally different design.

Just for the hell of it, look at the old Hi-Perf 396ci BBC.... they had port sizes up to 320cc!! They didn't suffer from any drivebility issues either. They were perfectly streetable.

 

Appreciate all the feedback, lots of great info

 

I don't think the heads would make that much difference. They won't ideal for a stock tpi, but I don't think they would kill anything. It makes more sense if you can't afford to buy everything at once to do it piecemeal to only buy one set of heads instead of buying a set of 180 cc heads and then when you can put a larger intaske and more cam in to switch to 195's.

 

what do the factory vortecs flow stock before i have then ported? i just nabed a 98 350 vortec engine and im looking at building it

 

dont port the vortecs. they find they flow best right outa the box. not worth the money... they show little if no gains. thats the crazy thing about the vortecs... they are best iron production head Gm has ever made. maybe a cumbustion chamber polish job but thats all i do... maybe a port match

i think they flow in the 220-230cfm range maybe. they flow really good for small ports and they flow really well in the .2-.4 lift range. a cam with over .5 lift doesnt really help the vortec heads breath.

the 195cc will suffer alil in the lower RPM ranges compared to a 180cc head... u wont kno tho bc u'll prob go with the 195cc. but if u were to have the 180cc head and then swap to the 195cc head u will notice sum power loss in the lower lift ranges and low to mid RPM ranges. the loss will be minimal tho due to the fact that u will use the heads for a larger engine eventually and u will prob pick up sum HP and rev alil higher in the upper RPM ranges with the 195cc over the 180cc. until u upgrade the engine. cam is ultimatly just as important

 

Vortecs don't benefit much with porting on the intake side UNLESS you port the exhaust side too... the exhaust ports are still the same crappy, weak port GM has used forever. Once the exhaust is properly ported, then the intake side will respond actually quite well to port work. This is the unique aspect of the Vortec heads that most people don't realize. The intake ports flow VERY well right out of the box and can't really flow MORE untill you open up the exhaust ports. Once the exhaust side is properly ported, they respond very well to porting on the intake side. You can't pull more in, untill you get more of the old stuff out.

A flowbench will not tell you this, but track times will.

 

So that vortecs are a good choice and what is the max lift i can go stock? and does anyone know what the exhaust port size exiting the head is?

 

Do you have any proof of this or are you just repeating what you've heard?

I guess my Trick Flow 195's are hurting my engine's velocity and i'd make how much more power if I swapped to the smaller 180's?

See my sticky thread "Quest for a better flowing TPI" to see just how much power the 195 heads are worth.

180 cc's are better for stock and mild engines. 195 cc's are better for built engines.

And stock Vortec heads are good to about .460" lift. Change the springs to Manley 22410-16 springs and 23652-16 retainers and you can get about .525" lift out of them.

 

I thought the same thing. Too many misconceptions with airflow floating around. I remember when everyone was scared of the 58mm and larger TB's unless you had something in a large cubic inch configuration. It would cause driveability, won't work, blah, blah. Heck I've seen a Monoblade tested on an LT1 w/ just a cam/mildly ported stock heads. It was worth 4rwhp over a 58mm and it just made it more responsive. I think people were trying to associate a carb to a TB and it's problems if you go to large. Not the case though.

 

I've driven bone stock LT1 and LT4 Corvettes various times, and the LT4 doesn't have any driveability issues compared to the LT1 (195cc heads VS 170cc heads here). The LT4 stock cam is actually milder than the LT1 cam of the same year ('96/97). It has less duration by a few degrees compared to the LT1 stick. The only significant difference between the LT1 and LT4 is the heads. By conventional logic, the LT4 should have pathetic throttle response and no power for at least 1-2 thousand RPMs above where the LT1 started making power. The LT4 should also make less torque.

I call BS on every one of those points. The throttle response was the same, the power came on at roughly the same RPM (within a few hundred RPM), they both felt basically the same untill you put your foot down... the LT4 made a bit more midrange power (2000+) and ALOT more topend. The LT1 is basically done at 5200-5400rpm. The LT4 pulled hard all the way to 6000rpm before it started to soften up like the LT1 did around 5200.