2" or 2.5 Ramhorn questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chewychevy67 · 08-07-2019, 10:03 PM

Not a header thread. Has anyone swapped from 2" to 2.5" ramhorns here on a 340 hp engine stock 400 auto tranny? Did you notice a big gain with the larger ones? If I stayed with my 2" horns am I going to be leaving a regrettable amount of power on the table vs putting the larger ones on? I can see it being a pain to do starter work with the straight down dumps on my 2wd if I opt for the larger ones.

AcampoDave · 08-08-2019, 05:00 PM

I have used both but my engines have always been rather mild so i can't tell you much sbout power gains, but what I can tell you is; my 2.5's were imported and of lesser quality than the GM 2's that I run today. The atcual port openings for the head on the 2.5's were smaller than the GM's and poorly cast. Ultimately, I pitched them in the scrap because they cracked in the middle, right above the doughnut flange.
Knowing this, if I ever get the urge for a more performace exhaust, I think I will try a set of Tru-Rams. https://www.walmart.com/ip/Tru-Ram-S...yABEgL5svD_BwE a bit pricey for sure, but pretty sweet.

chewychevy67 · 08-08-2019, 06:07 PM

I have access to both sets and both are original gm. I'm just not sure if the starter issues ( getting it in and out ater installed) are worth the added performance IF there is any with my engine setup. The bend right off the start in the exhaust is pretty tight.

AcampoDave · 08-08-2019, 06:23 PM

I never hsd any trouble with starter R&R and 2.5 inch piipe even with the stock unit. (I now use a compact starter.) But i suppose the skill of the exhaust installer would have some bearing on the outcome. I would also suspect that a 340 HP engine would certainly benefit from larger pipe.

**mattfranklin** · 08-08-2019, 07:55 PM

Great question. I'm looking forward to hearing answers. I have headers on mine now, but want to go with old Corvette ram's horns. Trying to make it as stock as I can with the GM 1960s/1970s parts bin.

Tom · 08-08-2019, 08:10 PM

Do you really go threw starters enough for this to be an issue?

chewychevy67 · 08-08-2019, 08:25 PM

I hope not. I had a 305 that gave me a ton of issues. I just dread taking the pipes off the down pipes to get at it once it's in the truck.

08-07-2019, 10:03 PM	#1
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,418	2" or 2.5 Ramhorn questions Not a header thread. Has anyone swapped from 2" to 2.5" ramhorns here on a 340 hp engine stock 400 auto tranny? Did you notice a big gain with the larger ones? If I stayed with my 2" horns am I going to be leaving a regrettable amount of power on the table vs putting the larger ones on? I can see it being a pain to do starter work with the straight down dumps on my 2wd if I opt for the larger ones.

08-08-2019, 05:00 PM	#2
AcampoDave Registered User Join Date: Feb 2013 Location: central California Posts: 2,727	Re: 2" or 2.5 Ramhorn questions I have used both but my engines have always been rather mild so i can't tell you much sbout power gains, but what I can tell you is; my 2.5's were imported and of lesser quality than the GM 2's that I run today. The atcual port openings for the head on the 2.5's were smaller than the GM's and poorly cast. Ultimately, I pitched them in the scrap because they cracked in the middle, right above the doughnut flange. Knowing this, if I ever get the urge for a more performace exhaust, I think I will try a set of Tru-Rams. https://www.walmart.com/ip/Tru-Ram-S...yABEgL5svD_BwE a bit pricey for sure, but pretty sweet. Last edited by AcampoDave; 08-08-2019 at 05:06 PM. Reason: Added link

08-08-2019, 06:07 PM	#3
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,418	Re: 2" or 2.5 Ramhorn questions I have access to both sets and both are original gm. I'm just not sure if the starter issues ( getting it in and out ater installed) are worth the added performance IF there is any with my engine setup. The bend right off the start in the exhaust is pretty tight.

08-08-2019, 06:23 PM	#4
AcampoDave Registered User Join Date: Feb 2013 Location: central California Posts: 2,727	Re: 2" or 2.5 Ramhorn questions I never hsd any trouble with starter R&R and 2.5 inch piipe even with the stock unit. (I now use a compact starter.) But i suppose the skill of the exhaust installer would have some bearing on the outcome. I would also suspect that a 340 HP engine would certainly benefit from larger pipe.

08-08-2019, 07:55 PM	#5
mattfranklin Senior Member Join Date: Dec 2011 Location: Moraga, CA Posts: 804	Re: 2" or 2.5 Ramhorn questions Great question. I'm looking forward to hearing answers. I have headers on mine now, but want to go with old Corvette ram's horns. Trying to make it as stock as I can with the GM 1960s/1970s parts bin. __________________ (Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340

08-08-2019, 08:10 PM	#6
Tom driving is in my blood Join Date: Dec 1999 Location: Mesa AZ Posts: 5,695	Re: 2" or 2.5 Ramhorn questions Do you really go threw starters enough for this to be an issue? __________________ -78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me.

08-08-2019, 08:25 PM	#7
chewychevy67 Registered User Join Date: Jan 2010 Location: Here Posts: 5,418	Re: 2" or 2.5 Ramhorn questions I hope not. I had a 305 that gave me a ton of issues. I just dread taking the pipes off the down pipes to get at it once it's in the truck.



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